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 35 matching lines @@
 class AnimationRegistrar;
 class HeadsUpDisplayLayer;
 class Layer;
 class LayerTreeHostImpl;
 class LayerTreeHostImplClient;
 class PrioritizedResourceManager;
 class PrioritizedResource;
 class Region;
 class ResourceProvider;
 class ResourceUpdateQueue;
+class ScrollbarLayer;
 class TopControlsManager;
 struct ScrollAndScaleSet;
 
 
 // Provides information on an Impl's rendering capabilities back to the LayerTreeHost
 struct CC_EXPORT RendererCapabilities {
     RendererCapabilities();
     ~RendererCapabilities();
 
     unsigned bestTextureFormat;
@@ skipping 23 matching lines @@
     bool needsOffscreenContext() const { return m_needsFilterContext || settings().acceleratePainting; }
 
     // LayerTreeHost interface to Proxy.
     void willBeginFrame() { m_client->willBeginFrame(); }
     void didBeginFrame();
     void updateAnimations(base::TimeTicks monotonicFrameBeginTime);
     void didStopFlinging();
     void layout();
     void beginCommitOnImplThread(LayerTreeHostImpl*);
     void finishCommitOnImplThread(LayerTreeHostImpl*);
+    void setPinchZoomScrollbarsBoundsAndPosition();
+    void createAndAddPinchZoomScrollbars();
     void willCommit();
     void commitComplete();
     scoped_ptr<OutputSurface> createOutputSurface();
     scoped_ptr<InputHandler> createInputHandler();
     virtual scoped_ptr<LayerTreeHostImpl> createLayerTreeHostImpl(LayerTreeHostImplClient*);
     void didLoseOutputSurface();
     enum RecreateResult {
         RecreateSucceeded,
         RecreateFailedButTryAgain,
         RecreateFailedAndGaveUp,
@@ skipping 35 matching lines @@
     void setNeedsAnimate();
     // virtual for testing
     virtual void setNeedsCommit();
     virtual void setNeedsFullTreeSync();
     void setNeedsRedraw();
     bool commitRequested() const;
 
     void setAnimationEvents(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime);
 
     Layer* rootLayer() { return m_rootLayer.get(); }
+    Layer* rootScrollLayer() const;

[enne (OOO), 2013/03/06 19:32:58]

const functions should not return non-const pointers.  Can you return a const
Layer*?

[wjmaclean, 2013/03/06 22:36:53]

Done.

+
     const Layer* rootLayer() const { return m_rootLayer.get(); }
     void setRootLayer(scoped_refptr<Layer>);
 
     const LayerTreeSettings& settings() const { return m_settings; }
 
     void setDebugState(const LayerTreeDebugState& debugState);
     const LayerTreeDebugState& debugState() const { return m_debugState; }
 
     void setViewportSize(const gfx::Size& layoutViewportSize, const gfx::Size& deviceViewportSize);
 
@@ skipping 82 matching lines @@
 
     int m_commitNumber;
     RenderingStats m_renderingStats;
 
     bool m_rendererInitialized;
     bool m_outputSurfaceLost;
     int m_numFailedRecreateAttempts;
 
     scoped_refptr<Layer> m_rootLayer;
     scoped_refptr<HeadsUpDisplayLayer> m_hudLayer;
+    scoped_refptr<ScrollbarLayer> m_pinchZoomScrollbarHorizontal;
+    scoped_refptr<ScrollbarLayer> m_pinchZoomScrollbarVertical;
 
     scoped_ptr<PrioritizedResourceManager> m_contentsTextureManager;
     scoped_ptr<PrioritizedResource> m_surfaceMemoryPlaceholder;
 
     base::WeakPtr<TopControlsManager> m_topControlsManagerWeakPtr;
 
     LayerTreeSettings m_settings;
     LayerTreeDebugState m_debugState;
 
     gfx::Size m_layoutViewportSize;
@@ skipping 17 matching lines @@
     size_t m_partialTextureUpdateRequests;
 
     scoped_ptr<AnimationRegistrar> m_animationRegistrar;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_H_