cc: Control activation from the Scheduler

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 31870ac48bd1e5e290fc620bbe1cf495903ec875..da1b3a5f72fea5797a746ffab0222a667183f988 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -61,7 +61,7 @@ class LayerTreeHostImplClient {
   virtual void OnSwapBuffersCompleteOnImplThread() = 0;
   virtual void BeginFrameOnImplThread(const BeginFrameArgs& args) = 0;
   virtual void OnCanDrawStateChanged(bool can_draw) = 0;
-  virtual void OnHasPendingTreeStateChanged(bool has_pending_tree) = 0;
+  virtual void NotifyReadyToActivate() = 0;
   virtual void SetNeedsRedrawOnImplThread() = 0;
   virtual void SetNeedsRedrawRectOnImplThread(gfx::Rect damage_rect) = 0;
   virtual void DidInitializeVisibleTileOnImplThread() = 0;
@@ -247,7 +247,7 @@ class CC_EXPORT LayerTreeHostImpl
   const LayerTreeImpl* recycle_tree() const { return recycle_tree_.get(); }
   virtual void CreatePendingTree();
   void UpdateVisibleTiles();
-  virtual void ActivatePendingTreeIfNeeded();
+  virtual void ActivatePendingTree();
 
   // Shortcuts to layers on the active tree.
   LayerImpl* RootLayer() const;
@@ -391,7 +391,6 @@ class CC_EXPORT LayerTreeHostImpl
       LayerTreeHostImplClient* client,
       Proxy* proxy,
       RenderingStatsInstrumentation* rendering_stats_instrumentation);
-  virtual void ActivatePendingTree();
 
   // Virtual for testing.
   virtual void AnimateLayers(base::TimeTicks monotonic_time,
@@ -471,7 +470,7 @@ class CC_EXPORT LayerTreeHostImpl
   scoped_ptr<LayerTreeImpl> active_tree_;
 
   // In impl-side painting mode, tree with possibly incomplete rasterized
-  // content. May be promoted to active by ActivatePendingTreeIfNeeded().
+  // content. May be promoted to active by ActivatePendingTree().
   scoped_ptr<LayerTreeImpl> pending_tree_;
 
   // In impl-side painting mode, inert tree with layers that can be recycled