Adaptively throttle texture uploads

cc/CCLayerTreeHost.h

Index: cc/CCLayerTreeHost.h
diff --git a/cc/CCLayerTreeHost.h b/cc/CCLayerTreeHost.h
index 09ff6a180c8dbc25bbdbfaa3d61a538413e07876..4efeaf98ab8ae773abec35a6842ab6de93f9d6e8 100644
--- a/cc/CCLayerTreeHost.h
+++ b/cc/CCLayerTreeHost.h
@@ -139,7 +139,7 @@ public:
     virtual void acquireLayerTextures();
     // Returns false if we should abort this frame due to initialization failure.
     bool initializeRendererIfNeeded();
-    void updateLayers(CCTextureUpdateQueue&, size_t contentsMemoryLimitBytes);
+    void updateLayers(CCTextureUpdateQueue&, size_t contentsMemoryLimitBytes, size_t maxPartialTextureUpdates);
 
     CCLayerTreeHostClient* client() { return m_client; }
 
@@ -232,7 +232,7 @@ private:
     bool paintLayerContents(const LayerList&, CCTextureUpdateQueue&);
     bool paintMasksForRenderSurface(LayerChromium*, CCTextureUpdateQueue&);
 
-    void updateLayers(LayerChromium*, CCTextureUpdateQueue&);
+    void updateLayers(LayerChromium*, CCTextureUpdateQueue&, size_t maxPartialTextureUpdates);
 
     void prioritizeTextures(const LayerList&, CCOverdrawMetrics&); 
     void setPrioritiesForSurfaces(size_t surfaceMemoryBytes);
@@ -283,6 +283,7 @@ private:
     bool m_hasTransparentBackground;
 
     TextureList m_deleteTextureAfterCommitList;
+    size_t m_maxPartialTextureUpdates;
     size_t m_partialTextureUpdateRequests;
 
     static bool s_needsFilterContext;