cc: Re-enable GPU rasterization after content veto.

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 26560e7facc54de59aeac0c710b117231a05baf0..6b8c160af444d39478f45ed552199fd1c3f34823 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -490,6 +490,10 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
  private:
   friend class LayerTreeHostSerializationTest;
 
+  // This is the number of consecutive frames in which we want the content to be
+  // suitable for GPU rasterization before re-enabling it.
+  enum { kNumFramesToConsiderBeforeGpuRasterization = 60 };
+
   void InitializeProxy(
       std::unique_ptr<Proxy> proxy,
       std::unique_ptr<BeginFrameSource> external_begin_frame_source);
@@ -616,6 +620,7 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
 
   uint32_t surface_id_namespace_;
   uint32_t next_surface_sequence_;
+  uint32_t num_consecutive_frames_suitable_for_gpu_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };