Reduce texture uploads during scrollbar invalidations.

cc/ScrollbarLayerChromium.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 ScrollbarLayerChromium_h
 #define ScrollbarLayerChromium_h
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "LayerChromium.h"
-#include "LayerTextureUpdater.h"
+#include "caching_bitmap_canvas_layer_texture_updater.h"
 #include <public/WebScrollbar.h>
 #include <public/WebScrollbarThemeGeometry.h>
 #include <public/WebScrollbarThemePainter.h>
 
 namespace cc {
 
 class Scrollbar;
 class ScrollbarThemeComposite;
 class CCTextureUpdateQueue;
 
@@ skipping 15 matching lines @@
 
     int scrollLayerId() const { return m_scrollLayerId; }
     void setScrollLayerId(int id) { m_scrollLayerId = id; }
 
     virtual ScrollbarLayerChromium* toScrollbarLayerChromium() OVERRIDE;
 
 protected:
     ScrollbarLayerChromium(PassOwnPtr<WebKit::WebScrollbar>, WebKit::WebScrollbarThemePainter, PassOwnPtr<WebKit::WebScrollbarThemeGeometry>, int scrollLayerId);
 
 private:
-    void updatePart(LayerTextureUpdater*, LayerTextureUpdater::Texture*, const IntRect&, CCTextureUpdateQueue&, CCRenderingStats&);
+    void updatePart(CachingBitmapCanvasLayerTextureUpdater*, LayerTextureUpdater::Texture*, const IntRect&, CCTextureUpdateQueue&, CCRenderingStats&);
     void createTextureUpdaterIfNeeded();
 
     OwnPtr<WebKit::WebScrollbar> m_scrollbar;
     WebKit::WebScrollbarThemePainter m_painter;
     OwnPtr<WebKit::WebScrollbarThemeGeometry> m_geometry;
     int m_scrollLayerId;
 
     GC3Denum m_textureFormat;
 
-    RefPtr<LayerTextureUpdater> m_backTrackUpdater;
-    RefPtr<LayerTextureUpdater> m_foreTrackUpdater;
-    RefPtr<LayerTextureUpdater> m_thumbUpdater;
+    RefPtr<CachingBitmapCanvasLayerTextureUpdater> m_backTrackUpdater;
+    RefPtr<CachingBitmapCanvasLayerTextureUpdater> m_foreTrackUpdater;
+    RefPtr<CachingBitmapCanvasLayerTextureUpdater> m_thumbUpdater;
 
     // All the parts of the scrollbar except the thumb
     OwnPtr<LayerTextureUpdater::Texture> m_backTrack;
     OwnPtr<LayerTextureUpdater::Texture> m_foreTrack;
     OwnPtr<LayerTextureUpdater::Texture> m_thumb;
 };
 
 }
 #endif // USE(ACCELERATED_COMPOSITING)
 
 #endif