cc: Check for completed raster tasks at interval.

cc/thread_proxy.h

Index: cc/thread_proxy.h
diff --git a/cc/thread_proxy.h b/cc/thread_proxy.h
index bf7d445eca781c3766daaa8dcf90210c2f296625..b5b045970f0a26fc5991d9e7ec56671c8982b98a 100644
--- a/cc/thread_proxy.h
+++ b/cc/thread_proxy.h
@@ -66,6 +66,7 @@ public:
     virtual void didUploadVisibleHighResolutionTileOnImplThread() OVERRIDE;
     virtual void setNeedsCommitOnImplThread() OVERRIDE;
     virtual void setNeedsManageTilesOnImplThread() OVERRIDE;
+    virtual void setNeedsCheckForCompletedRasterTasksOnImplThread() OVERRIDE;
     virtual void postAnimationEventsToMainThreadOnImplThread(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime) OVERRIDE;
     virtual bool reduceContentsTextureMemoryOnImplThread(size_t limitBytes, int priorityCutoff) OVERRIDE;
     virtual void reduceWastedContentsTextureMemoryOnImplThread() OVERRIDE;
@@ -134,6 +135,7 @@ private:
     void initializeRendererOnImplThread(CompletionEvent*, bool* initializeSucceeded, RendererCapabilities*);
     void layerTreeHostClosedOnImplThread(CompletionEvent*);
     void manageTilesOnImplThread();
+    void checkForCompletedRasterTasksOnImplThread();
     void setFullRootLayerDamageOnImplThread();
     void acquireLayerTexturesForMainThreadOnImplThread(CompletionEvent*);
     void recreateOutputSurfaceOnImplThread(CompletionEvent*, scoped_ptr<OutputSurface>, bool* recreateSucceeded, RendererCapabilities*);
@@ -159,6 +161,7 @@ private:
     bool m_texturesAcquired;
     bool m_inCompositeAndReadback;
     bool m_manageTilesPending;
+    bool m_checkForCompletedRasterTasksPending;
     // Weak pointer to use when posting tasks to the impl thread.
     base::WeakPtr<ThreadProxy> m_implThreadWeakPtr;