Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

cc/scrollbar_layer.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #ifndef CC_SCROLLBAR_LAYER_H_
 #define CC_SCROLLBAR_LAYER_H_
 
 #include "cc/cc_export.h"
 #include "cc/contents_scaling_layer.h"
 #include "cc/layer_updater.h"
 #include "cc/scrollbar_theme_painter.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebScrollbar.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebScrollbarThemeGeometry.h"
 
 namespace cc {
 class CachingBitmapContentLayerUpdater;
 class ResourceUpdateQueue;
 class Scrollbar;
 class ScrollbarThemeComposite;
 
 class CC_EXPORT ScrollbarLayer : public ContentsScalingLayer {
 public:
     virtual scoped_ptr<LayerImpl> createLayerImpl(LayerTreeImpl* treeImpl) OVERRIDE;
 
     static scoped_refptr<ScrollbarLayer> create(
         scoped_ptr<WebKit::WebScrollbar>,
         scoped_ptr<ScrollbarThemePainter>,
         scoped_ptr<WebKit::WebScrollbarThemeGeometry>,
+        int scrollLayerId, bool isPinchZoomScrollbar = false);
+
+    // This version of create() only called when creating pinch zoom scrollbars.
+    static scoped_refptr<ScrollbarLayer> create(
+        scoped_ptr<WebKit::WebScrollbar>,
+        scoped_ptr<ScrollbarThemePainter>,
         int scrollLayerId);
 
+    static void setDefaultGeometry(WebKit::WebScrollbarThemeGeometry*);
+    static WebKit::WebScrollbarThemeGeometry* cloneDefaultGeometry();
+    static void setDefaultUsesOverlayScrollbars(bool);
+    static bool defaultUsesOverlayScrollbars() { return s_usesOverlayScrollbars; }
+
     int scrollLayerId() const { return m_scrollLayerId; }
     void setScrollLayerId(int id);
 
     WebKit::WebScrollbar::Orientation orientation() const;
 
+    bool isPinchZoomScrollbar() { return m_isPinchZoomScrollbar; }
+
     // Layer interface
     virtual void setTexturePriorities(const PriorityCalculator&) OVERRIDE;
     virtual void update(ResourceUpdateQueue&, const OcclusionTracker*, RenderingStats*) OVERRIDE;
     virtual void setLayerTreeHost(LayerTreeHost*) OVERRIDE;
     virtual void pushPropertiesTo(LayerImpl*) OVERRIDE;
     virtual void calculateContentsScale(
         float idealContentsScale,
         bool animatingTransformToScreen,
         float* contentsScaleX,
         float* contentsScaleY,
         gfx::Size* contentBounds) OVERRIDE;
 
     virtual ScrollbarLayer* toScrollbarLayer() OVERRIDE;
 
 protected:
     ScrollbarLayer(
         scoped_ptr<WebKit::WebScrollbar>,
         scoped_ptr<ScrollbarThemePainter>,
         scoped_ptr<WebKit::WebScrollbarThemeGeometry>,
-        int scrollLayerId);
+        int scrollLayerId, bool isPinchZoomScrollbar);
     virtual ~ScrollbarLayer();
 
 private:
     void updatePart(CachingBitmapContentLayerUpdater*, LayerUpdater::Resource*, const gfx::Rect&, ResourceUpdateQueue&, RenderingStats*);
     void createUpdaterIfNeeded();
     gfx::Rect scrollbarLayerRectToContentRect(const gfx::Rect& layerRect) const;
 
     bool isDirty() const { return !m_dirtyRect.IsEmpty(); }
 
     int maxTextureSize();
     float clampScaleToMaxTextureSize(float scale);
 
+    static scoped_ptr<WebKit::WebScrollbarThemeGeometry> s_defaultGeometry;
+    static bool s_usesOverlayScrollbars;

[aelias_OOO_until_Jul13, 2013/02/06 19:02:45]

Please avoid statics.

+
     scoped_ptr<WebKit::WebScrollbar> m_scrollbar;
     scoped_ptr<ScrollbarThemePainter> m_painter;
     scoped_ptr<WebKit::WebScrollbarThemeGeometry> m_geometry;
     gfx::Size m_thumbSize;
     int m_scrollLayerId;
 
     unsigned m_textureFormat;
+    bool m_isPinchZoomScrollbar;
 
     gfx::RectF m_dirtyRect;
 
     scoped_refptr<CachingBitmapContentLayerUpdater> m_backTrackUpdater;
     scoped_refptr<CachingBitmapContentLayerUpdater> m_foreTrackUpdater;
     scoped_refptr<CachingBitmapContentLayerUpdater> m_thumbUpdater;
 
     // All the parts of the scrollbar except the thumb
     scoped_ptr<LayerUpdater::Resource> m_backTrack;
     scoped_ptr<LayerUpdater::Resource> m_foreTrack;
     scoped_ptr<LayerUpdater::Resource> m_thumb;
 };
 
 }
 #endif  // CC_SCROLLBAR_LAYER_H_