Imported QtWebKit TP3 (git b57bc6801f1876c3220d5a4bfea33d620d477443)

Change-Id: I3b1d8a2808782c9f34d50240000e20cb38d3680f
Reviewed-by: Konstantin Tokarev <annulen@yandex.ru>

1 files changed, 404 insertions, 342 deletions

diff --git a/Source/WebCore/page/DragController.cpp b/Source/WebCore/page/DragController.cpp
index 2537040d8..c4cbb67ef 100644
--- a/Source/WebCore/page/DragController.cpp
+++ b/Source/WebCore/page/DragController.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2007, 2009, 2010, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2007, 2009, 2010, 2013, 2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -10,10 +10,10 @@
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
- * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
@@ -26,31 +26,30 @@
 #include "config.h"
 #include "DragController.h"
 
-#if ENABLE(DRAG_SUPPORT)
+#include "HTMLAnchorElement.h"
+#include "SVGAElement.h"
 
+#if ENABLE(DRAG_SUPPORT)
 #include "CachedImage.h"
-#include "Clipboard.h"
-#include "ClipboardAccessPolicy.h"
 #include "CachedResourceLoader.h"
+#include "DataTransfer.h"
 #include "Document.h"
 #include "DocumentFragment.h"
 #include "DragActions.h"
 #include "DragClient.h"
 #include "DragData.h"
-#include "DragSession.h"
+#include "DragImage.h"
 #include "DragState.h"
 #include "Editor.h"
 #include "EditorClient.h"
-#include "Element.h"
 #include "EventHandler.h"
 #include "ExceptionCodePlaceholder.h"
 #include "FloatRect.h"
-#include "Frame.h"
 #include "FrameLoadRequest.h"
 #include "FrameLoader.h"
 #include "FrameSelection.h"
 #include "FrameView.h"
-#include "HTMLAnchorElement.h"
+#include "HTMLAttachmentElement.h"
 #include "HTMLImageElement.h"
 #include "HTMLInputElement.h"
 #include "HTMLNames.h"
@@ -59,8 +58,10 @@
 #include "HitTestResult.h"
 #include "Image.h"
 #include "ImageOrientation.h"
+#include "MainFrame.h"
 #include "MoveSelectionCommand.h"
 #include "Page.h"
+#include "Pasteboard.h"
 #include "PlatformKeyboardEvent.h"
 #include "PluginDocument.h"
 #include "PluginViewBase.h"
@@ -72,178 +73,183 @@
 #include "SecurityOrigin.h"
 #include "Settings.h"
 #include "ShadowRoot.h"
-#include "StylePropertySet.h"
+#include "StyleProperties.h"
 #include "Text.h"
 #include "TextEvent.h"
 #include "htmlediting.h"
 #include "markup.h"
 #include <wtf/CurrentTime.h>
 #include <wtf/RefPtr.h>
+#endif
 
 namespace WebCore {
 
-static PlatformMouseEvent createMouseEvent(DragData* dragData)
+bool isDraggableLink(const Element& element)
 {
-    bool shiftKey, ctrlKey, altKey, metaKey;
-    shiftKey = ctrlKey = altKey = metaKey = false;
-    int keyState = dragData->modifierKeyState();
-    shiftKey = static_cast<bool>(keyState & PlatformEvent::ShiftKey);
-    ctrlKey = static_cast<bool>(keyState & PlatformEvent::CtrlKey);
-    altKey = static_cast<bool>(keyState & PlatformEvent::AltKey);
-    metaKey = static_cast<bool>(keyState & PlatformEvent::MetaKey);
+    if (is<HTMLAnchorElement>(element))
+        return downcast<HTMLAnchorElement>(element).isLiveLink();
+    if (is<SVGAElement>(element))
+        return element.isLink();
+    return false;
+}
 
-    return PlatformMouseEvent(dragData->clientPosition(), dragData->globalPosition(),
+#if ENABLE(DRAG_SUPPORT)
+    
+static PlatformMouseEvent createMouseEvent(DragData& dragData)
+{
+    int keyState = dragData.modifierKeyState();
+    bool shiftKey = static_cast<bool>(keyState & PlatformEvent::ShiftKey);
+    bool ctrlKey = static_cast<bool>(keyState & PlatformEvent::CtrlKey);
+    bool altKey = static_cast<bool>(keyState & PlatformEvent::AltKey);
+    bool metaKey = static_cast<bool>(keyState & PlatformEvent::MetaKey);
+
+    return PlatformMouseEvent(dragData.clientPosition(), dragData.globalPosition(),
                               LeftButton, PlatformEvent::MouseMoved, 0, shiftKey, ctrlKey, altKey,
-                              metaKey, currentTime());
+                              metaKey, currentTime(), ForceAtClick);
 }
 
-DragController::DragController(Page* page, DragClient* client)
+DragController::DragController(Page& page, DragClient& client)
     : m_page(page)
     , m_client(client)
-    , m_documentUnderMouse(0)
-    , m_dragInitiator(0)
-    , m_fileInputElementUnderMouse(0)
+    , m_numberOfItemsToBeAccepted(0)
     , m_documentIsHandlingDrag(false)
     , m_dragDestinationAction(DragDestinationActionNone)
     , m_dragSourceAction(DragSourceActionNone)
     , m_didInitiateDrag(false)
     , m_sourceDragOperation(DragOperationNone)
 {
-    ASSERT(m_client);
 }
 
 DragController::~DragController()
 {
-    m_client->dragControllerDestroyed();
+    m_client.dragControllerDestroyed();
 }
 
-PassOwnPtr<DragController> DragController::create(Page* page, DragClient* client)
+static PassRefPtr<DocumentFragment> documentFragmentFromDragData(DragData& dragData, Frame& frame, Range& context, bool allowPlainText, bool& chosePlainText)
 {
-    return adoptPtr(new DragController(page, client));
-}
-
-static PassRefPtr<DocumentFragment> documentFragmentFromDragData(DragData* dragData, Frame* frame, RefPtr<Range> context,
-                                          bool allowPlainText, bool& chosePlainText)
-{
-    ASSERT(dragData);
     chosePlainText = false;
 
-    Document* document = context->ownerDocument();
-    ASSERT(document);
-    if (document && dragData->containsCompatibleContent()) {
-        if (PassRefPtr<DocumentFragment> fragment = dragData->asFragment(frame, context, allowPlainText, chosePlainText))
+    Document& document = context.ownerDocument();
+    if (dragData.containsCompatibleContent()) {
+        if (PassRefPtr<DocumentFragment> fragment = frame.editor().webContentFromPasteboard(*Pasteboard::createForDragAndDrop(dragData), context, allowPlainText, chosePlainText))
             return fragment;
 
-        if (dragData->containsURL(frame, DragData::DoNotConvertFilenames)) {
+        if (dragData.containsURL(DragData::DoNotConvertFilenames)) {
             String title;
-            String url = dragData->asURL(frame, DragData::DoNotConvertFilenames, &title);
+            String url = dragData.asURL(DragData::DoNotConvertFilenames, &title);
             if (!url.isEmpty()) {
-                RefPtr<HTMLAnchorElement> anchor = HTMLAnchorElement::create(document);
+                Ref<HTMLAnchorElement> anchor = HTMLAnchorElement::create(document);
                 anchor->setHref(url);
                 if (title.isEmpty()) {
                     // Try the plain text first because the url might be normalized or escaped.
-                    if (dragData->containsPlainText())
-                        title = dragData->asPlainText(frame);
+                    if (dragData.containsPlainText())
+                        title = dragData.asPlainText();
                     if (title.isEmpty())
                         title = url;
                 }
-                RefPtr<Node> anchorText = document->createTextNode(title);
-                anchor->appendChild(anchorText, IGNORE_EXCEPTION);
-                RefPtr<DocumentFragment> fragment = document->createDocumentFragment();
-                fragment->appendChild(anchor, IGNORE_EXCEPTION);
-                return fragment.get();
+                anchor->appendChild(document.createTextNode(title), IGNORE_EXCEPTION);
+                Ref<DocumentFragment> fragment = document.createDocumentFragment();
+                fragment->appendChild(WTFMove(anchor), IGNORE_EXCEPTION);
+                return fragment.ptr();
             }
         }
     }
-    if (allowPlainText && dragData->containsPlainText()) {
+    if (allowPlainText && dragData.containsPlainText()) {
         chosePlainText = true;
-        return createFragmentFromText(context.get(), dragData->asPlainText(frame)).get();
+        return createFragmentFromText(context, dragData.asPlainText()).ptr();
     }
 
-    return 0;
+    return nullptr;
 }
 
-bool DragController::dragIsMove(FrameSelection* selection, DragData* dragData)
+bool DragController::dragIsMove(FrameSelection& selection, DragData& dragData)
 {
-    return m_documentUnderMouse == m_dragInitiator && selection->isContentEditable() && selection->isRange() && !isCopyKeyDown(dragData);
+    const VisibleSelection& visibleSelection = selection.selection();
+    return m_documentUnderMouse == m_dragInitiator && visibleSelection.isContentEditable() && visibleSelection.isRange() && !isCopyKeyDown(dragData);
 }
 
-// FIXME: This method is poorly named.  We're just clearing the selection from the document this drag is exiting.
-void DragController::cancelDrag()
+void DragController::clearDragCaret()
 {
-    m_page->dragCaretController()->clear();
+    m_page.dragCaretController().clear();
 }
 
 void DragController::dragEnded()
 {
-    m_dragInitiator = 0;
+    m_dragInitiator = nullptr;
     m_didInitiateDrag = false;
-    m_page->dragCaretController()->clear();
+    clearDragCaret();
     
-    m_client->dragEnded();
+    m_client.dragEnded();
 }
 
-DragSession DragController::dragEntered(DragData* dragData)
+DragOperation DragController::dragEntered(DragData& dragData)
 {
     return dragEnteredOrUpdated(dragData);
 }
 
-void DragController::dragExited(DragData* dragData)
+void DragController::dragExited(DragData& dragData)
 {
-    ASSERT(dragData);
-    Frame* mainFrame = m_page->mainFrame();
-
-    if (RefPtr<FrameView> v = mainFrame->view()) {
-        ClipboardAccessPolicy policy = (!m_documentUnderMouse || m_documentUnderMouse->securityOrigin()->isLocal()) ? ClipboardReadable : ClipboardTypesReadable;
-        RefPtr<Clipboard> clipboard = Clipboard::create(policy, dragData, mainFrame);
-        clipboard->setSourceOperation(dragData->draggingSourceOperationMask());
-        mainFrame->eventHandler()->cancelDragAndDrop(createMouseEvent(dragData), clipboard.get());
-        clipboard->setAccessPolicy(ClipboardNumb);    // invalidate clipboard here for security
+    if (RefPtr<FrameView> v = m_page.mainFrame().view()) {
+#if ENABLE(DASHBOARD_SUPPORT)
+        DataTransferAccessPolicy policy = (m_page.mainFrame().settings().usesDashboardBackwardCompatibilityMode() && (!m_documentUnderMouse || m_documentUnderMouse->securityOrigin()->isLocal()))
+            ? DataTransferAccessPolicy::Readable : DataTransferAccessPolicy::TypesReadable;
+#else
+        DataTransferAccessPolicy policy = DataTransferAccessPolicy::TypesReadable;
+#endif
+        RefPtr<DataTransfer> dataTransfer = DataTransfer::createForDragAndDrop(policy, dragData);
+        dataTransfer->setSourceOperation(dragData.draggingSourceOperationMask());
+        m_page.mainFrame().eventHandler().cancelDragAndDrop(createMouseEvent(dragData), dataTransfer.get());
+        dataTransfer->setAccessPolicy(DataTransferAccessPolicy::Numb); // Invalidate dataTransfer here for security.
     }
-    mouseMovedIntoDocument(0);
+    mouseMovedIntoDocument(nullptr);
     if (m_fileInputElementUnderMouse)
         m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(false);
-    m_fileInputElementUnderMouse = 0;
+    m_fileInputElementUnderMouse = nullptr;
 }
 
-DragSession DragController::dragUpdated(DragData* dragData)
+DragOperation DragController::dragUpdated(DragData& dragData)
 {
     return dragEnteredOrUpdated(dragData);
 }
 
-bool DragController::performDrag(DragData* dragData)
+bool DragController::performDragOperation(DragData& dragData)
 {
-    ASSERT(dragData);
-    m_documentUnderMouse = m_page->mainFrame()->documentAtPoint(dragData->clientPosition());
+    m_documentUnderMouse = m_page.mainFrame().documentAtPoint(dragData.clientPosition());
+
+    ShouldOpenExternalURLsPolicy shouldOpenExternalURLsPolicy = ShouldOpenExternalURLsPolicy::ShouldNotAllow;
+    if (m_documentUnderMouse)
+        shouldOpenExternalURLsPolicy = m_documentUnderMouse->shouldOpenExternalURLsPolicyToPropagate();
+
     if ((m_dragDestinationAction & DragDestinationActionDHTML) && m_documentIsHandlingDrag) {
-        m_client->willPerformDragDestinationAction(DragDestinationActionDHTML, dragData);
-        RefPtr<Frame> mainFrame = m_page->mainFrame();
+        m_client.willPerformDragDestinationAction(DragDestinationActionDHTML, dragData);
+        Ref<MainFrame> mainFrame(m_page.mainFrame());
         bool preventedDefault = false;
         if (mainFrame->view()) {
             // Sending an event can result in the destruction of the view and part.
-            RefPtr<Clipboard> clipboard = Clipboard::create(ClipboardReadable, dragData, mainFrame.get());
-            clipboard->setSourceOperation(dragData->draggingSourceOperationMask());
-            preventedDefault = mainFrame->eventHandler()->performDragAndDrop(createMouseEvent(dragData), clipboard.get());
-            clipboard->setAccessPolicy(ClipboardNumb); // Invalidate clipboard here for security
+            RefPtr<DataTransfer> dataTransfer = DataTransfer::createForDragAndDrop(DataTransferAccessPolicy::Readable, dragData);
+            dataTransfer->setSourceOperation(dragData.draggingSourceOperationMask());
+            preventedDefault = mainFrame->eventHandler().performDragAndDrop(createMouseEvent(dragData), dataTransfer.get());
+            dataTransfer->setAccessPolicy(DataTransferAccessPolicy::Numb); // Invalidate dataTransfer here for security.
         }
         if (preventedDefault) {
-            m_documentUnderMouse = 0;
+            clearDragCaret();
+            m_documentUnderMouse = nullptr;
             return true;
         }
     }
 
     if ((m_dragDestinationAction & DragDestinationActionEdit) && concludeEditDrag(dragData)) {
-        m_documentUnderMouse = 0;
+        m_documentUnderMouse = nullptr;
         return true;
     }
 
-    m_documentUnderMouse = 0;
+    m_documentUnderMouse = nullptr;
 
     if (operationForLoad(dragData) == DragOperationNone)
         return false;
 
-    m_client->willPerformDragDestinationAction(DragDestinationActionLoad, dragData);
-    m_page->mainFrame()->loader()->load(FrameLoadRequest(m_page->mainFrame(), ResourceRequest(dragData->asURL(m_page->mainFrame()))));
+    m_client.willPerformDragDestinationAction(DragDestinationActionLoad, dragData);
+    m_page.mainFrame().loader().load(FrameLoadRequest(&m_page.mainFrame(), ResourceRequest(dragData.asURL()), shouldOpenExternalURLsPolicy));
     return true;
 }
 
@@ -254,40 +260,41 @@ void DragController::mouseMovedIntoDocument(Document* newDocument)
 
     // If we were over another document clear the selection
     if (m_documentUnderMouse)
-        cancelDrag();
+        clearDragCaret();
     m_documentUnderMouse = newDocument;
 }
 
-DragSession DragController::dragEnteredOrUpdated(DragData* dragData)
+DragOperation DragController::dragEnteredOrUpdated(DragData& dragData)
 {
-    ASSERT(dragData);
-    ASSERT(m_page->mainFrame());
-    mouseMovedIntoDocument(m_page->mainFrame()->documentAtPoint(dragData->clientPosition()));
+    mouseMovedIntoDocument(m_page.mainFrame().documentAtPoint(dragData.clientPosition()));
 
-    m_dragDestinationAction = m_client->actionMaskForDrag(dragData);
+    m_dragDestinationAction = m_client.actionMaskForDrag(dragData);
     if (m_dragDestinationAction == DragDestinationActionNone) {
-        cancelDrag(); // FIXME: Why not call mouseMovedIntoDocument(0)?
-        return DragSession();
+        clearDragCaret(); // FIXME: Why not call mouseMovedIntoDocument(nullptr)?
+        return DragOperationNone;
     }
 
-    DragSession dragSession;
-    m_documentIsHandlingDrag = tryDocumentDrag(dragData, m_dragDestinationAction, dragSession);
+    DragOperation dragOperation = DragOperationNone;
+    m_documentIsHandlingDrag = tryDocumentDrag(dragData, m_dragDestinationAction, dragOperation);
     if (!m_documentIsHandlingDrag && (m_dragDestinationAction & DragDestinationActionLoad))
-        dragSession.operation = operationForLoad(dragData);
-    return dragSession;
+        dragOperation = operationForLoad(dragData);
+    return dragOperation;
 }
 
-static HTMLInputElement* asFileInput(Node* node)
+static HTMLInputElement* asFileInput(Node& node)
 {
-    ASSERT(node);
+    if (!is<HTMLInputElement>(node))
+        return nullptr;
 
-    HTMLInputElement* inputElement = node->toInputElement();
+    auto* inputElement = &downcast<HTMLInputElement>(node);
 
     // If this is a button inside of the a file input, move up to the file input.
-    if (inputElement && inputElement->isTextButton() && inputElement->treeScope()->rootNode()->isShadowRoot())
-        inputElement = toShadowRoot(inputElement->treeScope()->rootNode())->host()->toInputElement();
+    if (inputElement->isTextButton() && is<ShadowRoot>(inputElement->treeScope().rootNode())) {
+        auto& host = *downcast<ShadowRoot>(inputElement->treeScope().rootNode()).host();
+        inputElement = is<HTMLInputElement>(host) ? &downcast<HTMLInputElement>(host) : nullptr;
+    }
 
-    return inputElement && inputElement->isFileUpload() ? inputElement : 0;
+    return inputElement && inputElement->isFileUpload() ? inputElement : nullptr;
 }
 
 // This can return null if an empty document is loaded.
@@ -295,25 +302,22 @@ static Element* elementUnderMouse(Document* documentUnderMouse, const IntPoint&
 {
     Frame* frame = documentUnderMouse->frame();
     float zoomFactor = frame ? frame->pageZoomFactor() : 1;
-    LayoutPoint point = roundedLayoutPoint(FloatPoint(p.x() * zoomFactor, p.y() * zoomFactor));
+    LayoutPoint point(p.x() * zoomFactor, p.y() * zoomFactor);
 
-    HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::DisallowShadowContent);
     HitTestResult result(point);
-    documentUnderMouse->renderView()->hitTest(request, result);
+    documentUnderMouse->renderView()->hitTest(HitTestRequest(), result);
 
-    Node* n = result.innerNode();
-    while (n && !n->isElementNode())
-        n = n->parentNode();
-    if (n)
-        n = n->deprecatedShadowAncestorNode();
+    Node* node = result.innerNode();
+    while (node && !is<Element>(*node))
+        node = node->parentNode();
+    if (node)
+        node = node->deprecatedShadowAncestorNode();
 
-    return toElement(n);
+    return downcast<Element>(node);
 }
 
-bool DragController::tryDocumentDrag(DragData* dragData, DragDestinationAction actionMask, DragSession& dragSession)
+bool DragController::tryDocumentDrag(DragData& dragData, DragDestinationAction actionMask, DragOperation& dragOperation)
 {
-    ASSERT(dragData);
-
     if (!m_documentUnderMouse)
         return false;
 
@@ -322,7 +326,7 @@ bool DragController::tryDocumentDrag(DragData* dragData, DragDestinationAction a
 
     bool isHandlingDrag = false;
     if (actionMask & DragDestinationActionDHTML) {
-        isHandlingDrag = tryDHTMLDrag(dragData, dragSession.operation);
+        isHandlingDrag = tryDHTMLDrag(dragData, dragOperation);
         // Do not continue if m_documentUnderMouse has been reset by tryDHTMLDrag.
         // tryDHTMLDrag fires dragenter event. The event listener that listens
         // to this event may create a nested message loop (open a modal dialog),
@@ -339,22 +343,22 @@ bool DragController::tryDocumentDrag(DragData* dragData, DragDestinationAction a
         return false;
 
     if (isHandlingDrag) {
-        m_page->dragCaretController()->clear();
+        clearDragCaret();
         return true;
     }
 
     if ((actionMask & DragDestinationActionEdit) && canProcessDrag(dragData)) {
-        if (dragData->containsColor()) {
-            dragSession.operation = DragOperationGeneric;
+        if (dragData.containsColor()) {
+            dragOperation = DragOperationGeneric;
             return true;
         }
 
-        IntPoint point = frameView->windowToContents(dragData->clientPosition());
+        IntPoint point = frameView->windowToContents(dragData.clientPosition());
         Element* element = elementUnderMouse(m_documentUnderMouse.get(), point);
         if (!element)
             return false;
         
-        HTMLInputElement* elementAsFileInput = asFileInput(element);
+        HTMLInputElement* elementAsFileInput = asFileInput(*element);
         if (m_fileInputElementUnderMouse != elementAsFileInput) {
             if (m_fileInputElementUnderMouse)
                 m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(false);
@@ -362,127 +366,125 @@ bool DragController::tryDocumentDrag(DragData* dragData, DragDestinationAction a
         }
         
         if (!m_fileInputElementUnderMouse)
-            m_page->dragCaretController()->setCaretPosition(m_documentUnderMouse->frame()->visiblePositionForPoint(point));
+            m_page.dragCaretController().setCaretPosition(m_documentUnderMouse->frame()->visiblePositionForPoint(point));
+        else
+            clearDragCaret();
 
-        Frame* innerFrame = element->document()->frame();
-        dragSession.operation = dragIsMove(innerFrame->selection(), dragData) ? DragOperationMove : DragOperationCopy;
-        dragSession.mouseIsOverFileInput = m_fileInputElementUnderMouse;
-        dragSession.numberOfItemsToBeAccepted = 0;
+        Frame* innerFrame = element->document().frame();
+        dragOperation = dragIsMove(innerFrame->selection(), dragData) ? DragOperationMove : DragOperationCopy;
+        m_numberOfItemsToBeAccepted = 0;
 
-        unsigned numberOfFiles = dragData->numberOfFiles();
+        unsigned numberOfFiles = dragData.numberOfFiles();
         if (m_fileInputElementUnderMouse) {
             if (m_fileInputElementUnderMouse->isDisabledFormControl())
-                dragSession.numberOfItemsToBeAccepted = 0;
+                m_numberOfItemsToBeAccepted = 0;
             else if (m_fileInputElementUnderMouse->multiple())
-                dragSession.numberOfItemsToBeAccepted = numberOfFiles;
+                m_numberOfItemsToBeAccepted = numberOfFiles;
             else if (numberOfFiles > 1)
-                dragSession.numberOfItemsToBeAccepted = 0;
+                m_numberOfItemsToBeAccepted = 0;
             else
-                dragSession.numberOfItemsToBeAccepted = 1;
+                m_numberOfItemsToBeAccepted = 1;
             
-            if (!dragSession.numberOfItemsToBeAccepted)
-                dragSession.operation = DragOperationNone;
-            m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(dragSession.numberOfItemsToBeAccepted);
+            if (!m_numberOfItemsToBeAccepted)
+                dragOperation = DragOperationNone;
+            m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(m_numberOfItemsToBeAccepted);
         } else {
             // We are not over a file input element. The dragged item(s) will only
             // be loaded into the view the number of dragged items is 1.
-            dragSession.numberOfItemsToBeAccepted = numberOfFiles != 1 ? 0 : 1;
+            m_numberOfItemsToBeAccepted = numberOfFiles != 1 ? 0 : 1;
         }
         
         return true;
     }
     
     // We are not over an editable region. Make sure we're clearing any prior drag cursor.
-    m_page->dragCaretController()->clear();
+    clearDragCaret();
     if (m_fileInputElementUnderMouse)
         m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(false);
-    m_fileInputElementUnderMouse = 0;
+    m_fileInputElementUnderMouse = nullptr;
     return false;
 }
 
 DragSourceAction DragController::delegateDragSourceAction(const IntPoint& rootViewPoint)
 {
-    m_dragSourceAction = m_client->dragSourceActionMaskForPoint(rootViewPoint);
+    m_dragSourceAction = m_client.dragSourceActionMaskForPoint(rootViewPoint);
     return m_dragSourceAction;
 }
 
-DragOperation DragController::operationForLoad(DragData* dragData)
+DragOperation DragController::operationForLoad(DragData& dragData)
 {
-    ASSERT(dragData);
-    Document* doc = m_page->mainFrame()->documentAtPoint(dragData->clientPosition());
+    Document* document = m_page.mainFrame().documentAtPoint(dragData.clientPosition());
 
     bool pluginDocumentAcceptsDrags = false;
 
-    if (doc && doc->isPluginDocument()) {
-        const Widget* widget = toPluginDocument(doc)->pluginWidget();
-        const PluginViewBase* pluginView = (widget && widget->isPluginViewBase()) ? static_cast<const PluginViewBase*>(widget) : 0;
+    if (is<PluginDocument>(document)) {
+        const Widget* widget = downcast<PluginDocument>(*document).pluginWidget();
+        const PluginViewBase* pluginView = is<PluginViewBase>(widget) ? downcast<PluginViewBase>(widget) : nullptr;
 
         if (pluginView)
             pluginDocumentAcceptsDrags = pluginView->shouldAllowNavigationFromDrags();
     }
 
-    if (doc && (m_didInitiateDrag || (doc->isPluginDocument() && !pluginDocumentAcceptsDrags) || doc->rendererIsEditable()))
+    if (document && (m_didInitiateDrag || (is<PluginDocument>(*document) && !pluginDocumentAcceptsDrags) || document->hasEditableStyle()))
         return DragOperationNone;
     return dragOperation(dragData);
 }
 
 static bool setSelectionToDragCaret(Frame* frame, VisibleSelection& dragCaret, RefPtr<Range>& range, const IntPoint& point)
 {
-    frame->selection()->setSelection(dragCaret);
-    if (frame->selection()->isNone()) {
+    frame->selection().setSelection(dragCaret);
+    if (frame->selection().selection().isNone()) {
         dragCaret = frame->visiblePositionForPoint(point);
-        frame->selection()->setSelection(dragCaret);
+        frame->selection().setSelection(dragCaret);
         range = dragCaret.toNormalizedRange();
     }
-    return !frame->selection()->isNone() && frame->selection()->isContentEditable();
+    return !frame->selection().isNone() && frame->selection().selection().isContentEditable();
 }
 
-bool DragController::dispatchTextInputEventFor(Frame* innerFrame, DragData* dragData)
+bool DragController::dispatchTextInputEventFor(Frame* innerFrame, DragData& dragData)
 {
-    ASSERT(m_page->dragCaretController()->hasCaret());
-    String text = m_page->dragCaretController()->isContentRichlyEditable() ? "" : dragData->asPlainText(innerFrame);
-    Node* target = innerFrame->editor().findEventTargetFrom(m_page->dragCaretController()->caretPosition());
-    return target->dispatchEvent(TextEvent::createForDrop(innerFrame->document()->domWindow(), text), IGNORE_EXCEPTION);
+    ASSERT(m_page.dragCaretController().hasCaret());
+    String text = m_page.dragCaretController().isContentRichlyEditable() ? emptyString() : dragData.asPlainText();
+    Node* target = innerFrame->editor().findEventTargetFrom(m_page.dragCaretController().caretPosition());
+    return target->dispatchEvent(TextEvent::createForDrop(innerFrame->document()->domWindow(), text));
 }
 
-bool DragController::concludeEditDrag(DragData* dragData)
+bool DragController::concludeEditDrag(DragData& dragData)
 {
-    ASSERT(dragData);
-
     RefPtr<HTMLInputElement> fileInput = m_fileInputElementUnderMouse;
     if (m_fileInputElementUnderMouse) {
         m_fileInputElementUnderMouse->setCanReceiveDroppedFiles(false);
-        m_fileInputElementUnderMouse = 0;
+        m_fileInputElementUnderMouse = nullptr;
     }
 
     if (!m_documentUnderMouse)
         return false;
 
-    IntPoint point = m_documentUnderMouse->view()->windowToContents(dragData->clientPosition());
+    IntPoint point = m_documentUnderMouse->view()->windowToContents(dragData.clientPosition());
     Element* element = elementUnderMouse(m_documentUnderMouse.get(), point);
     if (!element)
         return false;
-    RefPtr<Frame> innerFrame = element->ownerDocument()->frame();
+    RefPtr<Frame> innerFrame = element->document().frame();
     ASSERT(innerFrame);
 
-    if (m_page->dragCaretController()->hasCaret() && !dispatchTextInputEventFor(innerFrame.get(), dragData))
+    if (m_page.dragCaretController().hasCaret() && !dispatchTextInputEventFor(innerFrame.get(), dragData))
         return true;
 
-    if (dragData->containsColor()) {
-        Color color = dragData->asColor();
+    if (dragData.containsColor()) {
+        Color color = dragData.asColor();
         if (!color.isValid())
             return false;
-        RefPtr<Range> innerRange = innerFrame->selection()->toNormalizedRange();
-        RefPtr<MutableStylePropertySet> style = MutableStylePropertySet::create();
+        RefPtr<Range> innerRange = innerFrame->selection().toNormalizedRange();
+        RefPtr<MutableStyleProperties> style = MutableStyleProperties::create();
         style->setProperty(CSSPropertyColor, color.serialized(), false);
         if (!innerFrame->editor().shouldApplyStyle(style.get(), innerRange.get()))
             return false;
-        m_client->willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
+        m_client.willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
         innerFrame->editor().applyStyle(style.get(), EditActionSetColor);
         return true;
     }
 
-    if (dragData->containsFiles() && fileInput) {
+    if (dragData.containsFiles() && fileInput) {
         // fileInput should be the element we hit tested for, unless it was made
         // display:none in a drop event handler.
         ASSERT(fileInput == element || !fileInput->renderer());
@@ -492,90 +494,87 @@ bool DragController::concludeEditDrag(DragData* dragData)
         return fileInput->receiveDroppedFiles(dragData);
     }
 
-    if (!m_page->dragController()->canProcessDrag(dragData)) {
-        m_page->dragCaretController()->clear();
+    if (!m_page.dragController().canProcessDrag(dragData)) {
+        clearDragCaret();
         return false;
     }
 
-    VisibleSelection dragCaret = m_page->dragCaretController()->caretPosition();
-    m_page->dragCaretController()->clear();
+    VisibleSelection dragCaret = m_page.dragCaretController().caretPosition();
+    clearDragCaret();
     RefPtr<Range> range = dragCaret.toNormalizedRange();
-    RefPtr<Element> rootEditableElement = innerFrame->selection()->rootEditableElement();
+    RefPtr<Element> rootEditableElement = innerFrame->selection().selection().rootEditableElement();
 
     // For range to be null a WebKit client must have done something bad while
     // manually controlling drag behaviour
     if (!range)
         return false;
-    CachedResourceLoader* cachedResourceLoader = range->ownerDocument()->cachedResourceLoader();
-    ResourceCacheValidationSuppressor validationSuppressor(cachedResourceLoader);
+
+    ResourceCacheValidationSuppressor validationSuppressor(range->ownerDocument().cachedResourceLoader());
     if (dragIsMove(innerFrame->selection(), dragData) || dragCaret.isContentRichlyEditable()) {
         bool chosePlainText = false;
-        RefPtr<DocumentFragment> fragment = documentFragmentFromDragData(dragData, innerFrame.get(), range, true, chosePlainText);
+        RefPtr<DocumentFragment> fragment = documentFragmentFromDragData(dragData, *innerFrame, *range, true, chosePlainText);
         if (!fragment || !innerFrame->editor().shouldInsertFragment(fragment, range, EditorInsertActionDropped)) {
             return false;
         }
 
-        m_client->willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
+        m_client.willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
         if (dragIsMove(innerFrame->selection(), dragData)) {
             // NSTextView behavior is to always smart delete on moving a selection,
             // but only to smart insert if the selection granularity is word granularity.
             bool smartDelete = innerFrame->editor().smartInsertDeleteEnabled();
-            bool smartInsert = smartDelete && innerFrame->selection()->granularity() == WordGranularity && dragData->canSmartReplace();
+            bool smartInsert = smartDelete && innerFrame->selection().granularity() == WordGranularity && dragData.canSmartReplace();
             applyCommand(MoveSelectionCommand::create(fragment, dragCaret.base(), smartInsert, smartDelete));
         } else {
             if (setSelectionToDragCaret(innerFrame.get(), dragCaret, range, point)) {
                 ReplaceSelectionCommand::CommandOptions options = ReplaceSelectionCommand::SelectReplacement | ReplaceSelectionCommand::PreventNesting;
-                if (dragData->canSmartReplace())
+                if (dragData.canSmartReplace())
                     options |= ReplaceSelectionCommand::SmartReplace;
                 if (chosePlainText)
                     options |= ReplaceSelectionCommand::MatchStyle;
-                applyCommand(ReplaceSelectionCommand::create(m_documentUnderMouse.get(), fragment, options));
+                applyCommand(ReplaceSelectionCommand::create(*m_documentUnderMouse, WTFMove(fragment), options));
             }
         }
     } else {
-        String text = dragData->asPlainText(innerFrame.get());
+        String text = dragData.asPlainText();
         if (text.isEmpty() || !innerFrame->editor().shouldInsertText(text, range.get(), EditorInsertActionDropped)) {
             return false;
         }
 
-        m_client->willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
+        m_client.willPerformDragDestinationAction(DragDestinationActionEdit, dragData);
         if (setSelectionToDragCaret(innerFrame.get(), dragCaret, range, point))
-            applyCommand(ReplaceSelectionCommand::create(m_documentUnderMouse.get(), createFragmentFromText(range.get(), text),  ReplaceSelectionCommand::SelectReplacement | ReplaceSelectionCommand::MatchStyle | ReplaceSelectionCommand::PreventNesting));
+            applyCommand(ReplaceSelectionCommand::create(*m_documentUnderMouse, createFragmentFromText(*range, text),  ReplaceSelectionCommand::SelectReplacement | ReplaceSelectionCommand::MatchStyle | ReplaceSelectionCommand::PreventNesting));
     }
 
     if (rootEditableElement) {
-        if (Frame* frame = rootEditableElement->document()->frame())
-            frame->eventHandler()->updateDragStateAfterEditDragIfNeeded(rootEditableElement.get());
+        if (Frame* frame = rootEditableElement->document().frame())
+            frame->eventHandler().updateDragStateAfterEditDragIfNeeded(rootEditableElement.get());
     }
 
     return true;
 }
 
-bool DragController::canProcessDrag(DragData* dragData)
+bool DragController::canProcessDrag(DragData& dragData)
 {
-    ASSERT(dragData);
-
-    if (!dragData->containsCompatibleContent())
+    if (!dragData.containsCompatibleContent())
         return false;
 
-    IntPoint point = m_page->mainFrame()->view()->windowToContents(dragData->clientPosition());
+    IntPoint point = m_page.mainFrame().view()->windowToContents(dragData.clientPosition());
     HitTestResult result = HitTestResult(point);
-    if (!m_page->mainFrame()->contentRenderer())
+    if (!m_page.mainFrame().contentRenderer())
         return false;
 
-    result = m_page->mainFrame()->eventHandler()->hitTestResultAtPoint(point, HitTestRequest::ReadOnly | HitTestRequest::Active);
+    result = m_page.mainFrame().eventHandler().hitTestResultAtPoint(point, HitTestRequest::ReadOnly | HitTestRequest::Active);
 
     if (!result.innerNonSharedNode())
         return false;
 
-    if (dragData->containsFiles() && asFileInput(result.innerNonSharedNode()))
+    if (dragData.containsFiles() && asFileInput(*result.innerNonSharedNode()))
         return true;
 
-    if (result.innerNonSharedNode()->isPluginElement()) {
-        HTMLPlugInElement* plugin = static_cast<HTMLPlugInElement*>(result.innerNonSharedNode());
-        if (!plugin->canProcessDrag() && !result.innerNonSharedNode()->rendererIsEditable())
+    if (is<HTMLPlugInElement>(*result.innerNonSharedNode())) {
+        if (!downcast<HTMLPlugInElement>(result.innerNonSharedNode())->canProcessDrag() && !result.innerNonSharedNode()->hasEditableStyle())
             return false;
-    } else if (!result.innerNonSharedNode()->rendererIsEditable())
+    } else if (!result.innerNonSharedNode()->hasEditableStyle())
         return false;
 
     if (m_didInitiateDrag && m_documentUnderMouse == m_dragInitiator && result.isSelected())
@@ -603,118 +602,124 @@ static DragOperation defaultOperationForDrag(DragOperation srcOpMask)
     return DragOperationGeneric;
 }
 
-bool DragController::tryDHTMLDrag(DragData* dragData, DragOperation& operation)
+bool DragController::tryDHTMLDrag(DragData& dragData, DragOperation& operation)
 {
-    ASSERT(dragData);
     ASSERT(m_documentUnderMouse);
-    RefPtr<Frame> mainFrame = m_page->mainFrame();
+    Ref<MainFrame> mainFrame(m_page.mainFrame());
     RefPtr<FrameView> viewProtector = mainFrame->view();
     if (!viewProtector)
         return false;
 
-    ClipboardAccessPolicy policy = m_documentUnderMouse->securityOrigin()->isLocal() ? ClipboardReadable : ClipboardTypesReadable;
-    RefPtr<Clipboard> clipboard = Clipboard::create(policy, dragData, mainFrame.get());
-    DragOperation srcOpMask = dragData->draggingSourceOperationMask();
-    clipboard->setSourceOperation(srcOpMask);
+#if ENABLE(DASHBOARD_SUPPORT)
+    DataTransferAccessPolicy policy = (mainFrame->settings().usesDashboardBackwardCompatibilityMode() && m_documentUnderMouse->securityOrigin()->isLocal()) ?
+        DataTransferAccessPolicy::Readable : DataTransferAccessPolicy::TypesReadable;
+#else
+    DataTransferAccessPolicy policy = DataTransferAccessPolicy::TypesReadable;
+#endif
+    RefPtr<DataTransfer> dataTransfer = DataTransfer::createForDragAndDrop(policy, dragData);
+    DragOperation srcOpMask = dragData.draggingSourceOperationMask();
+    dataTransfer->setSourceOperation(srcOpMask);
 
     PlatformMouseEvent event = createMouseEvent(dragData);
-    if (!mainFrame->eventHandler()->updateDragAndDrop(event, clipboard.get())) {
-        clipboard->setAccessPolicy(ClipboardNumb);    // invalidate clipboard here for security
+    if (!mainFrame->eventHandler().updateDragAndDrop(event, dataTransfer.get())) {
+        dataTransfer->setAccessPolicy(DataTransferAccessPolicy::Numb); // Invalidate dataTransfer here for security.
         return false;
     }
 
-    operation = clipboard->destinationOperation();
-    if (clipboard->dropEffectIsUninitialized())
+    operation = dataTransfer->destinationOperation();
+    if (dataTransfer->dropEffectIsUninitialized())
         operation = defaultOperationForDrag(srcOpMask);
     else if (!(srcOpMask & operation)) {
         // The element picked an operation which is not supported by the source
         operation = DragOperationNone;
     }
 
-    clipboard->setAccessPolicy(ClipboardNumb);    // invalidate clipboard here for security
+    dataTransfer->setAccessPolicy(DataTransferAccessPolicy::Numb); // Invalidate dataTransfer here for security.
     return true;
 }
 
 Element* DragController::draggableElement(const Frame* sourceFrame, Element* startElement, const IntPoint& dragOrigin, DragState& state) const
 {
-    state.type = (sourceFrame->selection()->contains(dragOrigin)) ? DragSourceActionSelection : DragSourceActionNone;
+    state.type = (sourceFrame->selection().contains(dragOrigin)) ? DragSourceActionSelection : DragSourceActionNone;
     if (!startElement)
-        return 0;
+        return nullptr;
+#if ENABLE(ATTACHMENT_ELEMENT)
+    // Unlike image elements, attachment elements are immediately selected upon mouse down,
+    // but for those elements we still want to use the single element drag behavior as long as
+    // the element is the only content of the selection.
+    const VisibleSelection& selection = sourceFrame->selection().selection();
+    if (selection.isRange() && is<HTMLAttachmentElement>(selection.start().anchorNode()) && selection.start().anchorNode() == selection.end().anchorNode())
+        state.type = DragSourceActionNone;
+#endif
 
-    for (const RenderObject* renderer = startElement->renderer(); renderer; renderer = renderer->parent()) {
-        Node* node = renderer->nonPseudoNode();
-        if (!node)
-            // Anonymous render blocks don't correspond to actual DOM nodes, so we skip over them
-            // for the purposes of finding a draggable node.
+    for (auto* renderer = startElement->renderer(); renderer; renderer = renderer->parent()) {
+        Element* element = renderer->nonPseudoElement();
+        if (!element) {
+            // Anonymous render blocks don't correspond to actual DOM elements, so we skip over them
+            // for the purposes of finding a draggable element.
             continue;
-        if (!(state.type & DragSourceActionSelection) && node->isTextNode() && node->canStartSelection())
-            // In this case we have a click in the unselected portion of text. If this text is
-            // selectable, we want to start the selection process instead of looking for a parent
-            // to try to drag.
-            return 0;
-        if (node->isElementNode()) {
-            EUserDrag dragMode = renderer->style()->userDrag();
-            if ((m_dragSourceAction & DragSourceActionDHTML) && dragMode == DRAG_ELEMENT) {
-                state.type = static_cast<DragSourceAction>(state.type | DragSourceActionDHTML);
-                return toElement(node);
+        }
+        EUserDrag dragMode = renderer->style().userDrag();
+        if ((m_dragSourceAction & DragSourceActionDHTML) && dragMode == DRAG_ELEMENT) {
+            state.type = static_cast<DragSourceAction>(state.type | DragSourceActionDHTML);
+            return element;
+        }
+        if (dragMode == DRAG_AUTO) {
+            if ((m_dragSourceAction & DragSourceActionImage)
+                && is<HTMLImageElement>(*element)
+                && sourceFrame->settings().loadsImagesAutomatically()) {
+                state.type = static_cast<DragSourceAction>(state.type | DragSourceActionImage);
+                return element;
             }
-            if (dragMode == DRAG_AUTO) {
-                if ((m_dragSourceAction & DragSourceActionImage)
-                    && isHTMLImageElement(node)
-                    && sourceFrame->settings()
-                    && sourceFrame->settings()->loadsImagesAutomatically()) {
-                    state.type = static_cast<DragSourceAction>(state.type | DragSourceActionImage);
-                    return toElement(node);
-                }
-                if ((m_dragSourceAction & DragSourceActionLink)
-                    && isHTMLAnchorElement(node)
-                    && toHTMLAnchorElement(node)->isLiveLink()) {
-                    state.type = static_cast<DragSourceAction>(state.type | DragSourceActionLink);
-                    return toElement(node);
-                }
+            if ((m_dragSourceAction & DragSourceActionLink) && isDraggableLink(*element)) {
+                state.type = static_cast<DragSourceAction>(state.type | DragSourceActionLink);
+                return element;
             }
+#if ENABLE(ATTACHMENT_ELEMENT)
+            if ((m_dragSourceAction & DragSourceActionAttachment)
+                && is<HTMLAttachmentElement>(*element)
+                && downcast<HTMLAttachmentElement>(*element).file()) {
+                state.type = static_cast<DragSourceAction>(state.type | DragSourceActionAttachment);
+                return element;
+            }
+#endif
         }
     }
 
     // We either have nothing to drag or we have a selection and we're not over a draggable element.
-    return (state.type & DragSourceActionSelection) ? startElement : 0;
+    return (state.type & DragSourceActionSelection) ? startElement : nullptr;
 }
 
-static CachedImage* getCachedImage(Element* element)
+static CachedImage* getCachedImage(Element& element)
 {
-    ASSERT(element);
-    RenderObject* renderer = element->renderer();
-    if (!renderer || !renderer->isImage())
-        return 0;
-    RenderImage* image = toRenderImage(renderer);
-    return image->cachedImage();
+    RenderObject* renderer = element.renderer();
+    if (!is<RenderImage>(renderer))
+        return nullptr;
+    auto& image = downcast<RenderImage>(*renderer);
+    return image.cachedImage();
 }
 
-static Image* getImage(Element* element)
+static Image* getImage(Element& element)
 {
-    ASSERT(element);
     CachedImage* cachedImage = getCachedImage(element);
     // Don't use cachedImage->imageForRenderer() here as that may return BitmapImages for cached SVG Images.
     // Users of getImage() want access to the SVGImage, in order to figure out the filename extensions,
     // which would be empty when asking the cached BitmapImages.
     return (cachedImage && !cachedImage->errorOccurred()) ?
-        cachedImage->image() : 0;
+        cachedImage->image() : nullptr;
 }
 
-static void prepareClipboardForImageDrag(Frame* source, Clipboard* clipboard, Element* node, const KURL& linkURL, const KURL& imageURL, const String& label)
+static void selectElement(Element& element)
 {
-    if (node->isContentRichlyEditable()) {
-        RefPtr<Range> range = source->document()->createRange();
-        range->selectNode(node, ASSERT_NO_EXCEPTION);
-        source->selection()->setSelection(VisibleSelection(range.get(), DOWNSTREAM));
-    }
-    clipboard->declareAndWriteDragImage(node, !linkURL.isEmpty() ? linkURL : imageURL, label, source);
+    RefPtr<Range> range = element.document().createRange();
+    range->selectNode(&element);
+    element.document().frame()->selection().setSelection(VisibleSelection(*range, DOWNSTREAM));
 }
 
 static IntPoint dragLocForDHTMLDrag(const IntPoint& mouseDraggedPoint, const IntPoint& dragOrigin, const IntPoint& dragImageOffset, bool isLinkImage)
 {
     // dragImageOffset is the cursor position relative to the lower-left corner of the image.
-#if PLATFORM(MAC)
+#if PLATFORM(COCOA)
     // We add in the Y dimension because we are a flipped view, so adding moves the image down.
     const int yOffset = dragImageOffset.y();
 #else
@@ -727,13 +732,13 @@ static IntPoint dragLocForDHTMLDrag(const IntPoint& mouseDraggedPoint, const Int
     return IntPoint(dragOrigin.x() - dragImageOffset.x(), dragOrigin.y() + yOffset);
 }
 
-static IntPoint dragLocForSelectionDrag(Frame* src)
+static IntPoint dragLocForSelectionDrag(Frame& src)
 {
-    IntRect draggingRect = enclosingIntRect(src->selection()->bounds());
+    IntRect draggingRect = enclosingIntRect(src.selection().selectionBounds());
     int xpos = draggingRect.maxX();
     xpos = draggingRect.x() < xpos ? draggingRect.x() : xpos;
     int ypos = draggingRect.maxY();
-#if PLATFORM(MAC)
+#if PLATFORM(COCOA)
     // Deal with flipped coordinates on Mac
     ypos = draggingRect.y() > ypos ? draggingRect.y() : ypos;
 #else
@@ -742,34 +747,50 @@ static IntPoint dragLocForSelectionDrag(Frame* src)
     return IntPoint(xpos, ypos);
 }
 
-bool DragController::startDrag(Frame* src, const DragState& state, DragOperation srcOp, const PlatformMouseEvent& dragEvent, const IntPoint& dragOrigin)
+bool DragController::startDrag(Frame& src, const DragState& state, DragOperation srcOp, const PlatformMouseEvent& dragEvent, const IntPoint& dragOrigin)
 {
-    ASSERT(src);
-
-    if (!src->view() || !src->contentRenderer())
+    if (!src.view() || !src.contentRenderer() || !state.source)
         return false;
 
-    HitTestResult hitTestResult = src->eventHandler()->hitTestResultAtPoint(dragOrigin, HitTestRequest::ReadOnly | HitTestRequest::Active);
-    if (!state.source->contains(hitTestResult.innerNode()))
+    HitTestResult hitTestResult = src.eventHandler().hitTestResultAtPoint(dragOrigin, HitTestRequest::ReadOnly | HitTestRequest::Active);
+
+    // FIXME(136836): Investigate whether all elements should use the containsIncludingShadowDOM() path here.
+    bool includeShadowDOM = false;
+#if ENABLE(VIDEO)
+    includeShadowDOM = state.source->isMediaElement();
+#endif
+    bool sourceContainsHitNode;
+    if (!includeShadowDOM)
+        sourceContainsHitNode = state.source->contains(hitTestResult.innerNode());
+    else
+        sourceContainsHitNode = state.source->containsIncludingShadowDOM(hitTestResult.innerNode());
+
+    if (!sourceContainsHitNode)
         // The original node being dragged isn't under the drag origin anymore... maybe it was
         // hidden or moved out from under the cursor. Regardless, we don't want to start a drag on
         // something that's not actually under the drag origin.
         return false;
-    KURL linkURL = hitTestResult.absoluteLinkURL();
-    KURL imageURL = hitTestResult.absoluteImageURL();
+    URL linkURL = hitTestResult.absoluteLinkURL();
+    URL imageURL = hitTestResult.absoluteImageURL();
+#if ENABLE(ATTACHMENT_ELEMENT)
+    URL attachmentURL = hitTestResult.absoluteAttachmentURL();
+    m_draggingAttachmentURL = URL();
+#endif
 
-    IntPoint mouseDraggedPoint = src->view()->windowToContents(dragEvent.position());
+    IntPoint mouseDraggedPoint = src.view()->windowToContents(dragEvent.position());
 
-    m_draggingImageURL = KURL();
+    m_draggingImageURL = URL();
     m_sourceDragOperation = srcOp;
 
-    DragImageRef dragImage = 0;
+    DragImageRef dragImage = nullptr;
     IntPoint dragLoc(0, 0);
     IntPoint dragImageOffset(0, 0);
 
-    Clipboard* clipboard = state.clipboard.get();
+    ASSERT(state.dataTransfer);
+
+    DataTransfer& dataTransfer = *state.dataTransfer;
     if (state.type == DragSourceActionDHTML)
-        dragImage = clipboard->createDragImage(dragImageOffset);
+        dragImage = dataTransfer.createDragImage(dragImageOffset);
     if (state.type == DragSourceActionSelection || !imageURL.isEmpty() || !linkURL.isEmpty())
         // Selection, image, and link drags receive a default set of allowed drag operations that
         // follows from:
@@ -785,79 +806,117 @@ bool DragController::startDrag(Frame* src, const DragState& state, DragOperation
 
     bool startedDrag = true; // optimism - we almost always manage to start the drag
 
-    Element* element = state.source.get();
+    ASSERT(state.source);
+    Element& element = *state.source;
 
     Image* image = getImage(element);
     if (state.type == DragSourceActionSelection) {
-        if (!clipboard->hasData()) {
-            RefPtr<Range> selectionRange = src->selection()->toNormalizedRange();
+        if (!dataTransfer.pasteboard().hasData()) {
+            // FIXME: This entire block is almost identical to the code in Editor::copy, and the code should be shared.
+
+            RefPtr<Range> selectionRange = src.selection().toNormalizedRange();
             ASSERT(selectionRange);
 
-            src->editor().willWriteSelectionToPasteboard(selectionRange.get());
+            src.editor().willWriteSelectionToPasteboard(selectionRange.get());
 
-            if (enclosingTextFormControl(src->selection()->start()))
-                clipboard->writePlainText(src->editor().selectedTextForClipboard());
-            else
-                clipboard->writeRange(selectionRange.get(), src);
+            if (enclosingTextFormControl(src.selection().selection().start()))
+                dataTransfer.pasteboard().writePlainText(src.editor().selectedTextForDataTransfer(), Pasteboard::CannotSmartReplace);
+            else {
+#if PLATFORM(COCOA) || PLATFORM(EFL) || PLATFORM(GTK) || PLATFORM(QT)
+                src.editor().writeSelectionToPasteboard(dataTransfer.pasteboard());
+#else
+                // FIXME: Convert all other platforms to match Mac and delete this.
+                dataTransfer.pasteboard().writeSelection(*selectionRange, src.editor().canSmartCopyOrDelete(), src, IncludeImageAltTextForDataTransfer);
+#endif
+            }
 
-            src->editor().didWriteSelectionToPasteboard();
+            src.editor().didWriteSelectionToPasteboard();
         }
-        m_client->willPerformDragSourceAction(DragSourceActionSelection, dragOrigin, clipboard);
+        m_client.willPerformDragSourceAction(DragSourceActionSelection, dragOrigin, dataTransfer);
         if (!dragImage) {
-            dragImage = dissolveDragImageToFraction(src->dragImageForSelection(), DragImageAlpha);
+            dragImage = dissolveDragImageToFraction(createDragImageForSelection(src), DragImageAlpha);
             dragLoc = dragLocForSelectionDrag(src);
             m_dragOffset = IntPoint(dragOrigin.x() - dragLoc.x(), dragOrigin.y() - dragLoc.y());
         }
-        doSystemDrag(dragImage, dragLoc, dragOrigin, clipboard, src, false);
-    } else if (!imageURL.isEmpty() && element && image && !image->isNull()
-               && (m_dragSourceAction & DragSourceActionImage)) {
+
+        if (!dragImage)
+            return false;
+
+        doSystemDrag(dragImage, dragLoc, dragOrigin, dataTransfer, src, false);
+    } else if (!src.document()->securityOrigin()->canDisplay(linkURL)) {
+        src.document()->addConsoleMessage(MessageSource::Security, MessageLevel::Error, "Not allowed to drag local resource: " + linkURL.stringCenterEllipsizedToLength());
+        startedDrag = false;
+    } else if (!imageURL.isEmpty() && image && !image->isNull() && (m_dragSourceAction & DragSourceActionImage)) {
         // We shouldn't be starting a drag for an image that can't provide an extension.
         // This is an early detection for problems encountered later upon drop.
         ASSERT(!image->filenameExtension().isEmpty());
-        if (!clipboard->hasData()) {
+        if (!dataTransfer.pasteboard().hasData()) {
             m_draggingImageURL = imageURL;
-            prepareClipboardForImageDrag(src, clipboard, element, linkURL, imageURL, hitTestResult.altDisplayString());
+            if (element.isContentRichlyEditable())
+                selectElement(element);
+            declareAndWriteDragImage(dataTransfer, element, !linkURL.isEmpty() ? linkURL : imageURL, hitTestResult.altDisplayString());
         }
 
-        m_client->willPerformDragSourceAction(DragSourceActionImage, dragOrigin, clipboard);
+        m_client.willPerformDragSourceAction(DragSourceActionImage, dragOrigin, dataTransfer);
 
         if (!dragImage) {
             IntRect imageRect = hitTestResult.imageRect();
-            imageRect.setLocation(m_page->mainFrame()->view()->rootViewToContents(src->view()->contentsToRootView(imageRect.location())));
-            doImageDrag(element, dragOrigin, hitTestResult.imageRect(), clipboard, src, m_dragOffset);
-        } else
+            imageRect.setLocation(m_page.mainFrame().view()->rootViewToContents(src.view()->contentsToRootView(imageRect.location())));
+            doImageDrag(element, dragOrigin, hitTestResult.imageRect(), dataTransfer, src, m_dragOffset);
+        } else {
             // DHTML defined drag image
-            doSystemDrag(dragImage, dragLoc, dragOrigin, clipboard, src, false);
-
+            doSystemDrag(dragImage, dragLoc, dragOrigin, dataTransfer, src, false);
+        }
     } else if (!linkURL.isEmpty() && (m_dragSourceAction & DragSourceActionLink)) {
-        if (!clipboard->hasData())
-            // Simplify whitespace so the title put on the clipboard resembles what the user sees
+        if (!dataTransfer.pasteboard().hasData()) {
+            // Simplify whitespace so the title put on the dataTransfer resembles what the user sees
             // on the web page. This includes replacing newlines with spaces.
-            clipboard->writeURL(linkURL, hitTestResult.textContent().simplifyWhiteSpace(), src);
+            src.editor().copyURL(linkURL, hitTestResult.textContent().simplifyWhiteSpace(), dataTransfer.pasteboard());
+        }
 
-        if (src->selection()->isCaret() && src->selection()->isContentEditable()) {
+        const VisibleSelection& sourceSelection = src.selection().selection();
+        if (sourceSelection.isCaret() && sourceSelection.isContentEditable()) {
             // a user can initiate a drag on a link without having any text
             // selected.  In this case, we should expand the selection to
             // the enclosing anchor element
-            Position pos = src->selection()->base();
+            Position pos = sourceSelection.base();
             Node* node = enclosingAnchorElement(pos);
             if (node)
-                src->selection()->setSelection(VisibleSelection::selectionFromContentsOfNode(node));
+                src.selection().setSelection(VisibleSelection::selectionFromContentsOfNode(node));
         }
 
-        m_client->willPerformDragSourceAction(DragSourceActionLink, dragOrigin, clipboard);
+        m_client.willPerformDragSourceAction(DragSourceActionLink, dragOrigin, dataTransfer);
         if (!dragImage) {
-            dragImage = createDragImageForLink(linkURL, hitTestResult.textContent(), src->settings() ? src->settings()->fontRenderingMode() : NormalRenderingMode);
+            dragImage = createDragImageForLink(linkURL, hitTestResult.textContent(), src.settings().fontRenderingMode());
             IntSize size = dragImageSize(dragImage);
             m_dragOffset = IntPoint(-size.width() / 2, -LinkDragBorderInset);
             dragLoc = IntPoint(mouseDraggedPoint.x() + m_dragOffset.x(), mouseDraggedPoint.y() + m_dragOffset.y());
+            // Later code expects the drag image to be scaled by device's scale factor.
+            dragImage = scaleDragImage(dragImage, FloatSize(m_page.deviceScaleFactor(), m_page.deviceScaleFactor()));
+        }
+        doSystemDrag(dragImage, dragLoc, mouseDraggedPoint, dataTransfer, src, true);
+#if ENABLE(ATTACHMENT_ELEMENT)
+    } else if (!attachmentURL.isEmpty() && (m_dragSourceAction & DragSourceActionAttachment)) {
+        if (!dataTransfer.pasteboard().hasData()) {
+            m_draggingAttachmentURL = attachmentURL;
+            selectElement(element);
+            declareAndWriteAttachment(dataTransfer, element, attachmentURL);
         }
-        doSystemDrag(dragImage, dragLoc, mouseDraggedPoint, clipboard, src, true);
+        
+        m_client.willPerformDragSourceAction(DragSourceActionAttachment, dragOrigin, dataTransfer);
+        
+        if (!dragImage) {
+            dragImage = dissolveDragImageToFraction(createDragImageForSelection(src), DragImageAlpha);
+            dragLoc = dragLocForSelectionDrag(src);
+            m_dragOffset = IntPoint(dragOrigin.x() - dragLoc.x(), dragOrigin.y() - dragLoc.y());
+        }
+        doSystemDrag(dragImage, dragLoc, dragOrigin, dataTransfer, src, false);
+#endif
     } else if (state.type == DragSourceActionDHTML) {
         if (dragImage) {
             ASSERT(m_dragSourceAction & DragSourceActionDHTML);
-            m_client->willPerformDragSourceAction(DragSourceActionDHTML, dragOrigin, clipboard);
-            doSystemDrag(dragImage, dragLoc, dragOrigin, clipboard, src, false);
+            m_client.willPerformDragSourceAction(DragSourceActionDHTML, dragOrigin, dataTransfer);
+            doSystemDrag(dragImage, dragLoc, dragOrigin, dataTransfer, src, false);
         } else
             startedDrag = false;
     } else {
@@ -871,57 +930,60 @@ bool DragController::startDrag(Frame* src, const DragState& state, DragOperation
     return startedDrag;
 }
 
-void DragController::doImageDrag(Element* element, const IntPoint& dragOrigin, const IntRect& rect, Clipboard* clipboard, Frame* frame, IntPoint& dragImageOffset)
+void DragController::doImageDrag(Element& element, const IntPoint& dragOrigin, const IntRect& layoutRect, DataTransfer& dataTransfer, Frame& frame, IntPoint& dragImageOffset)
 {
     IntPoint mouseDownPoint = dragOrigin;
-    DragImageRef dragImage = 0;
-    IntPoint origin;
+    DragImageRef dragImage = nullptr;
+    IntPoint scaledOrigin;
+
+    if (!element.renderer())
+        return;
+
+    ImageOrientationDescription orientationDescription(element.renderer()->shouldRespectImageOrientation(), element.renderer()->style().imageOrientation());
 
     Image* image = getImage(element);
     if (image && image->size().height() * image->size().width() <= MaxOriginalImageArea
-        && (dragImage = createDragImageFromImage(image, element->renderer() ? element->renderer()->shouldRespectImageOrientation() : DoNotRespectImageOrientation))) {
-        IntSize originalSize = rect.size();
-        origin = rect.location();
+        && (dragImage = createDragImageFromImage(image, element.renderer() ? orientationDescription : ImageOrientationDescription()))) {
 
-        dragImage = fitDragImageToMaxSize(dragImage, rect.size(), maxDragImageSize());
+        dragImage = fitDragImageToMaxSize(dragImage, layoutRect.size(), maxDragImageSize());
+        IntSize fittedSize = dragImageSize(dragImage);
+
+        dragImage = scaleDragImage(dragImage, FloatSize(m_page.deviceScaleFactor(), m_page.deviceScaleFactor()));
         dragImage = dissolveDragImageToFraction(dragImage, DragImageAlpha);
-        IntSize newSize = dragImageSize(dragImage);
-
-        // Properly orient the drag image and orient it differently if it's smaller than the original
-        float scale = newSize.width() / (float)originalSize.width();
-        float dx = origin.x() - mouseDownPoint.x();
-        dx *= scale;
-        origin.setX((int)(dx + 0.5));
-#if PLATFORM(MAC)
-        //Compensate for accursed flipped coordinates in cocoa
-        origin.setY(origin.y() + originalSize.height());
+
+        // Properly orient the drag image and orient it differently if it's smaller than the original.
+        float scale = fittedSize.width() / (float)layoutRect.width();
+        float dx = scale * (layoutRect.x() - mouseDownPoint.x());
+        float originY = layoutRect.y();
+#if PLATFORM(COCOA)
+        // Compensate for accursed flipped coordinates in Cocoa.
+        originY += layoutRect.height();
 #endif
-        float dy = origin.y() - mouseDownPoint.y();
-        dy *= scale;
-        origin.setY((int)(dy + 0.5));
+        float dy = scale * (originY - mouseDownPoint.y());
+        scaledOrigin = IntPoint((int)(dx + 0.5), (int)(dy + 0.5));
     } else {
         if (CachedImage* cachedImage = getCachedImage(element)) {
             dragImage = createDragImageIconForCachedImageFilename(cachedImage->response().suggestedFilename());
             if (dragImage)
-                origin = IntPoint(DragIconRightInset - dragImageSize(dragImage).width(), DragIconBottomInset);
+                scaledOrigin = IntPoint(DragIconRightInset - dragImageSize(dragImage).width(), DragIconBottomInset);
         }
     }
 
-    dragImageOffset = mouseDownPoint + origin;
-    doSystemDrag(dragImage, dragImageOffset, dragOrigin, clipboard, frame, false);
+    dragImageOffset = mouseDownPoint + scaledOrigin;
+    doSystemDrag(dragImage, dragImageOffset, dragOrigin, dataTransfer, frame, false);
 
     deleteDragImage(dragImage);
 }
 
-void DragController::doSystemDrag(DragImageRef image, const IntPoint& dragLoc, const IntPoint& eventPos, Clipboard* clipboard, Frame* frame, bool forLink)
+void DragController::doSystemDrag(DragImageRef image, const IntPoint& dragLoc, const IntPoint& eventPos, DataTransfer& dataTransfer, Frame& frame, bool forLink)
 {
     m_didInitiateDrag = true;
-    m_dragInitiator = frame->document();
+    m_dragInitiator = frame.document();
     // Protect this frame and view, as a load may occur mid drag and attempt to unload this frame
-    RefPtr<Frame> frameProtector = m_page->mainFrame();
+    Ref<MainFrame> frameProtector(m_page.mainFrame());
     RefPtr<FrameView> viewProtector = frameProtector->view();
-    m_client->startDrag(image, viewProtector->rootViewToContents(frame->view()->contentsToRootView(dragLoc)),
-        viewProtector->rootViewToContents(frame->view()->contentsToRootView(eventPos)), clipboard, frameProtector.get(), forLink);
+    m_client.startDrag(image, viewProtector->rootViewToContents(frame.view()->contentsToRootView(dragLoc)),
+        viewProtector->rootViewToContents(frame.view()->contentsToRootView(eventPos)), dataTransfer, frameProtector.get(), forLink);
     // DragClient::startDrag can cause our Page to dispear, deallocating |this|.
     if (!frameProtector->page())
         return;
@@ -932,7 +994,7 @@ void DragController::doSystemDrag(DragImageRef image, const IntPoint& dragLoc, c
 // Manual drag caret manipulation
 void DragController::placeDragCaret(const IntPoint& windowPoint)
 {
-    mouseMovedIntoDocument(m_page->mainFrame()->documentAtPoint(windowPoint));
+    mouseMovedIntoDocument(m_page.mainFrame().documentAtPoint(windowPoint));
     if (!m_documentUnderMouse)
         return;
     Frame* frame = m_documentUnderMouse->frame();
@@ -941,9 +1003,9 @@ void DragController::placeDragCaret(const IntPoint& windowPoint)
         return;
     IntPoint framePoint = frameView->windowToContents(windowPoint);
 
-    m_page->dragCaretController()->setCaretPosition(frame->visiblePositionForPoint(framePoint));
+    m_page.dragCaretController().setCaretPosition(frame->visiblePositionForPoint(framePoint));
 }
 
-} // namespace WebCore
-
 #endif // ENABLE(DRAG_SUPPORT)
+
+} // namespace WebCore