1 files changed, 64 insertions, 44 deletions

diff --git a/Source/WebCore/accessibility/AccessibilityScrollView.cpp b/Source/WebCore/accessibility/AccessibilityScrollView.cpp
index f158506b3..ed5aa5844 100644
--- a/Source/WebCore/accessibility/AccessibilityScrollView.cpp
+++ b/Source/WebCore/accessibility/AccessibilityScrollView.cpp
@@ -51,12 +51,12 @@ AccessibilityScrollView::~AccessibilityScrollView()
 void AccessibilityScrollView::detach(AccessibilityDetachmentType detachmentType, AXObjectCache* cache)
 {
     AccessibilityObject::detach(detachmentType, cache);
-    m_scrollView = 0;
+    m_scrollView = nullptr;
 }
 
-PassRefPtr<AccessibilityScrollView> AccessibilityScrollView::create(ScrollView* view)
+Ref<AccessibilityScrollView> AccessibilityScrollView::create(ScrollView* view)
 {
-    return adoptRef(new AccessibilityScrollView(view));
+    return adoptRef(*new AccessibilityScrollView(view));
 }
     
 AccessibilityObject* AccessibilityScrollView::scrollBar(AccessibilityOrientation orientation)
@@ -64,13 +64,15 @@ AccessibilityObject* AccessibilityScrollView::scrollBar(AccessibilityOrientation
     updateScrollbars();
     
     switch (orientation) {
+    // ARIA 1.1 Elements with the role scrollbar have an implicit aria-orientation value of vertical.
+    case AccessibilityOrientationUndefined:
     case AccessibilityOrientationVertical:
-        return m_verticalScrollbar ? m_verticalScrollbar.get() : 0;
+        return m_verticalScrollbar ? m_verticalScrollbar.get() : nullptr;
     case AccessibilityOrientationHorizontal:
-        return m_horizontalScrollbar ? m_horizontalScrollbar.get() : 0;
+        return m_horizontalScrollbar ? m_horizontalScrollbar.get() : nullptr;
     }
     
-    return 0;
+    return nullptr;
 }
 
 // If this is WebKit1 then the native scroll view needs to return the
@@ -106,13 +108,11 @@ void AccessibilityScrollView::setFocused(bool focused)
 
 void AccessibilityScrollView::updateChildrenIfNecessary()
 {
-    if (m_childrenDirty)
-        clearChildren();
-
-    if (!m_haveChildren)
-        addChildren();
-    
-    updateScrollbars();
+    // Always update our children when asked for them so that we don't inadvertently cache them after
+    // a new web area has been created for this scroll view (like when moving back and forth through history).
+    // Since a ScrollViews children will always be relatively small and limited this should not be a performance problem.
+    clearChildren();
+    addChildren();
 }
 
 void AccessibilityScrollView::updateScrollbars()
@@ -124,14 +124,14 @@ void AccessibilityScrollView::updateScrollbars()
         m_horizontalScrollbar = addChildScrollbar(m_scrollView->horizontalScrollbar());
     else if (!m_scrollView->horizontalScrollbar() && m_horizontalScrollbar) {
         removeChildScrollbar(m_horizontalScrollbar.get());
-        m_horizontalScrollbar = 0;
+        m_horizontalScrollbar = nullptr;
     }
 
     if (m_scrollView->verticalScrollbar() && !m_verticalScrollbar)
         m_verticalScrollbar = addChildScrollbar(m_scrollView->verticalScrollbar());
     else if (!m_scrollView->verticalScrollbar() && m_verticalScrollbar) {
         removeChildScrollbar(m_verticalScrollbar.get());
-        m_verticalScrollbar = 0;
+        m_verticalScrollbar = nullptr;
     }
 }
     
@@ -147,19 +147,23 @@ void AccessibilityScrollView::removeChildScrollbar(AccessibilityObject* scrollba
 AccessibilityScrollbar* AccessibilityScrollView::addChildScrollbar(Scrollbar* scrollbar)
 {
     if (!scrollbar)
-        return 0;
+        return nullptr;
     
-    AccessibilityScrollbar* scrollBarObject = toAccessibilityScrollbar(axObjectCache()->getOrCreate(scrollbar));
-    scrollBarObject->setParent(this);
-    m_children.append(scrollBarObject);
-    return scrollBarObject;
+    AXObjectCache* cache = axObjectCache();
+    if (!cache)
+        return nullptr;
+
+    auto& scrollBarObject = downcast<AccessibilityScrollbar>(*cache->getOrCreate(scrollbar));
+    scrollBarObject.setParent(this);
+    m_children.append(&scrollBarObject);
+    return &scrollBarObject;
 }
         
 void AccessibilityScrollView::clearChildren()
 {
     AccessibilityObject::clearChildren();
-    m_verticalScrollbar = 0;
-    m_horizontalScrollbar = 0;
+    m_verticalScrollbar = nullptr;
+    m_horizontalScrollbar = nullptr;
 }
 
 bool AccessibilityScrollView::computeAccessibilityIsIgnored() const
@@ -185,21 +189,24 @@ void AccessibilityScrollView::addChildren()
 
 AccessibilityObject* AccessibilityScrollView::webAreaObject() const
 {
-    if (!m_scrollView || !m_scrollView->isFrameView())
-        return 0;
+    if (!is<FrameView>(m_scrollView))
+        return nullptr;
     
-    Document* doc = toFrameView(m_scrollView)->frame().document();
-    if (!doc || !doc->hasLivingRenderTree())
-        return 0;
+    Document* document = downcast<FrameView>(*m_scrollView).frame().document();
+    if (!document || !document->hasLivingRenderTree())
+        return nullptr;
 
-    return axObjectCache()->getOrCreate(doc);
+    if (AXObjectCache* cache = axObjectCache())
+        return cache->getOrCreate(document);
+    
+    return nullptr;
 }
 
 AccessibilityObject* AccessibilityScrollView::accessibilityHitTest(const IntPoint& point) const
 {
     AccessibilityObject* webArea = webAreaObject();
     if (!webArea)
-        return 0;
+        return nullptr;
     
     if (m_horizontalScrollbar && m_horizontalScrollbar->elementRect().contains(point))
         return m_horizontalScrollbar.get();
@@ -214,39 +221,52 @@ LayoutRect AccessibilityScrollView::elementRect() const
     if (!m_scrollView)
         return LayoutRect();
 
-    return m_scrollView->frameRect();
+    LayoutRect rect = m_scrollView->frameRect();
+    float topContentInset = m_scrollView->topContentInset();
+    // Top content inset pushes the frame down and shrinks it.
+    rect.move(0, topContentInset);
+    rect.contract(0, topContentInset);
+    return rect;
 }
 
 FrameView* AccessibilityScrollView::documentFrameView() const
 {
-    if (!m_scrollView || !m_scrollView->isFrameView())
-        return 0;
+    if (!is<FrameView>(m_scrollView))
+        return nullptr;
     
-    return toFrameView(m_scrollView);
+    return downcast<FrameView>(m_scrollView);
 }    
 
 AccessibilityObject* AccessibilityScrollView::parentObject() const
 {
-    if (!m_scrollView || !m_scrollView->isFrameView())
-        return 0;
-    
-    HTMLFrameOwnerElement* owner = toFrameView(m_scrollView)->frame().ownerElement();
+    if (!is<FrameView>(m_scrollView))
+        return nullptr;
+
+    AXObjectCache* cache = axObjectCache();
+    if (!cache)
+        return nullptr;
+
+    HTMLFrameOwnerElement* owner = downcast<FrameView>(*m_scrollView).frame().ownerElement();
     if (owner && owner->renderer())
-        return axObjectCache()->getOrCreate(owner);
+        return cache->getOrCreate(owner);
 
-    return 0;
+    return nullptr;
 }
     
 AccessibilityObject* AccessibilityScrollView::parentObjectIfExists() const
 {
-    if (!m_scrollView || !m_scrollView->isFrameView())
-        return 0;
+    if (!is<FrameView>(m_scrollView))
+        return nullptr;
     
-    HTMLFrameOwnerElement* owner = toFrameView(m_scrollView)->frame().ownerElement();
+    AXObjectCache* cache = axObjectCache();
+    if (!cache)
+        return nullptr;
+
+    HTMLFrameOwnerElement* owner = downcast<FrameView>(m_scrollView)->frame().ownerElement();
     if (owner && owner->renderer())
-        return axObjectCache()->get(owner);
+        return cache->get(owner);
     
-    return 0;
+    return nullptr;
 }
 
 ScrollableArea* AccessibilityScrollView::getScrollableAreaIfScrollable() const