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diff --git a/chromium/third_party/blink/renderer/platform/scroll/scrollbar_theme.h b/chromium/third_party/blink/renderer/platform/scroll/scrollbar_theme.h
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+/*
+ * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    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 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 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
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCROLL_SCROLLBAR_THEME_H_
+#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCROLL_SCROLLBAR_THEME_H_
+
+#include "third_party/blink/public/platform/web_scrollbar_buttons_placement.h"
+#include "third_party/blink/renderer/platform/geometry/int_rect.h"
+#include "third_party/blink/renderer/platform/graphics/paint/display_item.h"
+#include "third_party/blink/renderer/platform/platform_export.h"
+#include "third_party/blink/renderer/platform/scroll/scroll_types.h"
+#include "third_party/blink/renderer/platform/scroll/scrollbar.h"
+
+namespace blink {
+
+class CullRect;
+class GraphicsContext;
+class WebMouseEvent;
+
+class PLATFORM_EXPORT ScrollbarTheme {
+  WTF_MAKE_NONCOPYABLE(ScrollbarTheme);
+  USING_FAST_MALLOC(ScrollbarTheme);
+
+ public:
+  ScrollbarTheme() = default;
+  virtual ~ScrollbarTheme() = default;
+
+  // If true, then scrollbars with this theme will be painted every time
+  // Scrollbar::setNeedsPaintInvalidation is called. If false, then only parts
+  // which are explicitly invalidated will be repainted.
+  virtual bool ShouldRepaintAllPartsOnInvalidation() const { return true; }
+
+  virtual void UpdateEnabledState(const ScrollbarThemeClient&) {}
+
+  virtual bool Paint(const Scrollbar&, GraphicsContext&, const CullRect&);
+
+  virtual ScrollbarPart HitTest(const ScrollbarThemeClient&, const IntPoint&);
+
+  // This returns a fixed value regardless of device-scale-factor.
+  // This returns thickness when scrollbar is painted.  i.e. It's not 0 even in
+  // overlay scrollbar mode.
+  // See also Scrollbar::scrollbarThickness().
+  virtual int ScrollbarThickness(ScrollbarControlSize = kRegularScrollbar) {
+    return 0;
+  }
+  virtual int ScrollbarMargin() const { return 0; }
+
+  virtual WebScrollbarButtonsPlacement ButtonsPlacement() const {
+    return kWebScrollbarButtonsPlacementSingle;
+  }
+
+  virtual bool SupportsControlTints() const { return false; }
+  virtual bool UsesOverlayScrollbars() const { return false; }
+  virtual void UpdateScrollbarOverlayColorTheme(const ScrollbarThemeClient&) {}
+
+  // If true, scrollbars that become invisible (i.e. overlay scrollbars that
+  // fade out) should be marked as disabled. This option exists since Mac and
+  // Aura overlays implement the fade out differently, with Mac painting code
+  // fading out the scrollbars. Aura scrollbars require disabling the scrollbar
+  // to prevent painting it.
+  virtual bool ShouldDisableInvisibleScrollbars() const { return true; }
+
+  virtual bool InvalidateOnMouseEnterExit() { return false; }
+  virtual bool InvalidateOnWindowActiveChange() const { return false; }
+
+  // Returns parts of the scrollbar which must be repainted following a change
+  // in the thumb position, given scroll positions before and after.
+  virtual ScrollbarPart InvalidateOnThumbPositionChange(
+      const ScrollbarThemeClient&,
+      float old_position,
+      float new_position) const {
+    return kAllParts;
+  }
+
+  virtual void PaintScrollCorner(GraphicsContext&,
+                                 const DisplayItemClient&,
+                                 const IntRect& corner_rect);
+  virtual void PaintTickmarks(GraphicsContext&,
+                              const Scrollbar&,
+                              const IntRect&);
+
+  virtual bool ShouldCenterOnThumb(const ScrollbarThemeClient&,
+                                   const WebMouseEvent&);
+  virtual bool ShouldSnapBackToDragOrigin(const ScrollbarThemeClient&,
+                                          const WebMouseEvent&);
+  virtual bool ShouldDragDocumentInsteadOfThumb(const ScrollbarThemeClient&,
+                                                const WebMouseEvent&) {
+    return false;
+  }
+
+  // The position of the thumb relative to the track.
+  int ThumbPosition(const ScrollbarThemeClient& scrollbar) {
+    return ThumbPosition(scrollbar, scrollbar.CurrentPos());
+  }
+  virtual double OverlayScrollbarFadeOutDelaySeconds() const;
+  virtual double OverlayScrollbarFadeOutDurationSeconds() const;
+  // The position the thumb would have, relative to the track, at the specified
+  // scroll position.
+  virtual int ThumbPosition(const ScrollbarThemeClient&, float scroll_position);
+  // The length of the thumb along the axis of the scrollbar.
+  virtual int ThumbLength(const ScrollbarThemeClient&);
+  // The position of the track relative to the scrollbar.
+  virtual int TrackPosition(const ScrollbarThemeClient&);
+  // The length of the track along the axis of the scrollbar.
+  virtual int TrackLength(const ScrollbarThemeClient&);
+  // The opacity to be applied to the thumb. A theme overriding ThumbOpacity()
+  // should also override PaintThumbWithOpacity().
+  virtual float ThumbOpacity(const ScrollbarThemeClient&) const { return 1.0f; }
+
+  virtual bool HasButtons(const ScrollbarThemeClient&) = 0;
+  virtual bool HasThumb(const ScrollbarThemeClient&) = 0;
+
+  virtual IntRect BackButtonRect(const ScrollbarThemeClient&,
+                                 ScrollbarPart,
+                                 bool painting = false) = 0;
+  virtual IntRect ForwardButtonRect(const ScrollbarThemeClient&,
+                                    ScrollbarPart,
+                                    bool painting = false) = 0;
+  virtual IntRect TrackRect(const ScrollbarThemeClient&,
+                            bool painting = false) = 0;
+  virtual IntRect ThumbRect(const ScrollbarThemeClient&);
+  virtual int ThumbThickness(const ScrollbarThemeClient&);
+
+  virtual int MinimumThumbLength(const ScrollbarThemeClient&) = 0;
+
+  virtual void SplitTrack(const ScrollbarThemeClient&,
+                          const IntRect& track,
+                          IntRect& start_track,
+                          IntRect& thumb,
+                          IntRect& end_track);
+
+  virtual void PaintScrollbarBackground(GraphicsContext&, const Scrollbar&) {}
+  virtual void PaintTrackBackground(GraphicsContext&,
+                                    const Scrollbar&,
+                                    const IntRect&) {}
+  virtual void PaintTrackPiece(GraphicsContext&,
+                               const Scrollbar&,
+                               const IntRect&,
+                               ScrollbarPart) {}
+  virtual void PaintButton(GraphicsContext&,
+                           const Scrollbar&,
+                           const IntRect&,
+                           ScrollbarPart) {}
+  virtual void PaintThumb(GraphicsContext&, const Scrollbar&, const IntRect&) {}
+
+  // Paint the thumb with ThumbOpacity() applied.
+  virtual void PaintThumbWithOpacity(GraphicsContext& context,
+                                     const Scrollbar& scrollbar,
+                                     const IntRect& rect) {
+    // By default this method just calls PaintThumb(). A theme with custom
+    // ThumbOpacity() should override this method to apply the opacity.
+    DCHECK_EQ(1.0f, ThumbOpacity(scrollbar));
+    PaintThumb(context, scrollbar, rect);
+  }
+
+  virtual int MaxOverlapBetweenPages() {
+    return std::numeric_limits<int>::max();
+  }
+
+  virtual double InitialAutoscrollTimerDelay() { return 0.25; }
+  virtual double AutoscrollTimerDelay() { return 0.05; }
+
+  virtual IntRect ConstrainTrackRectToTrackPieces(const ScrollbarThemeClient&,
+                                                  const IntRect& rect) {
+    return rect;
+  }
+
+  virtual void RegisterScrollbar(ScrollbarThemeClient&) {}
+  virtual void UnregisterScrollbar(ScrollbarThemeClient&) {}
+
+  virtual bool IsMockTheme() const { return false; }
+
+  virtual bool UsesNinePatchThumbResource() const { return false; }
+
+  // For a nine-patch scrollbar, this defines the painting canvas size which the
+  // painting code will use to paint the scrollbar into. The actual scrollbar
+  // dimensions will be ignored for purposes of painting since the resource can
+  // be then resized without a repaint.
+  virtual IntSize NinePatchThumbCanvasSize(const ScrollbarThemeClient&) const {
+    NOTREACHED();
+    return IntSize();
+  }
+
+  // For a nine-patch resource, the aperture defines the center patch that will
+  // be stretched out.
+  virtual IntRect NinePatchThumbAperture(const ScrollbarThemeClient&) const {
+    NOTREACHED();
+    return IntRect();
+  }
+
+  // Warning: Please call Page::GetScrollbarTheme instead of call this method
+  // directly since we support different native scrollbar theme base on page
+  // settings. See crrev.com/c/646727, this function will eventually be removed.
+  static ScrollbarTheme& DeprecatedStaticGetTheme();
+
+  static void SetMockScrollbarsEnabled(bool flag);
+  static bool MockScrollbarsEnabled();
+
+ protected:
+  virtual int TickmarkBorderWidth() { return 0; }
+  static DisplayItem::Type ButtonPartToDisplayItemType(ScrollbarPart);
+  static DisplayItem::Type TrackPiecePartToDisplayItemType(ScrollbarPart);
+
+ private:
+  static ScrollbarTheme&
+  NativeTheme();  // Must be implemented to return the correct theme subclass.
+  static bool g_mock_scrollbars_enabled_;
+};
+
+}  // namespace blink
+#endif