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

cc/layer_tree_host.h

 // Copyright 2011 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_LAYER_TREE_HOST_H_
 #define CC_LAYER_TREE_HOST_H_
 
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 29 matching lines @@
 #endif // COMPILER
 
 namespace cc {
 
 class Layer;
 class LayerTreeHostImpl;
 class LayerTreeHostImplClient;
 class PrioritizedResourceManager;
 class ResourceUpdateQueue;
 class HeadsUpDisplayLayer;
+class PinchZoomScrollbarLayer;
 class Region;
 struct ScrollAndScaleSet;
 
 
 // Provides information on an Impl's rendering capabilities back to the LayerTreeHost
 struct CC_EXPORT RendererCapabilities {
     RendererCapabilities();
     ~RendererCapabilities();
 
     GLenum bestTextureFormat;
@@ skipping 177 matching lines @@
     int m_commitNumber;
     RenderingStats m_renderingStats;
 
     bool m_rendererInitialized;
     bool m_outputSurfaceLost;
     int m_numTimesRecreateShouldFail;
     int m_numFailedRecreateAttempts;
 
     scoped_refptr<Layer> m_rootLayer;
     scoped_refptr<HeadsUpDisplayLayer> m_hudLayer;
+    scoped_refptr<PinchZoomScrollbarLayer> m_pinchZoomScrollbarVertical;
+    scoped_refptr<PinchZoomScrollbarLayer> m_pinchZoomScrollbarHorizontal;
 
     scoped_ptr<PrioritizedResourceManager> m_contentsTextureManager;
     scoped_ptr<PrioritizedResource> m_surfaceMemoryPlaceholder;
 
     LayerTreeSettings m_settings;
     LayerTreeDebugState m_debugState;
 
     gfx::Size m_layoutViewportSize;
     gfx::Size m_deviceViewportSize;
     float m_deviceScaleFactor;
@@ skipping 15 matching lines @@
     size_t m_partialTextureUpdateRequests;
 
     static bool s_needsFilterContext;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_H_