cc: Split animating and drawing into separate actions

cc/trees/thread_proxy.h

Index: cc/trees/thread_proxy.h
diff --git a/cc/trees/thread_proxy.h b/cc/trees/thread_proxy.h
index aab7a43988ed5e5597efc47c0760eb55f5e3e426..381e2be3627d56ef7d32bfce186bc9057c838aa4 100644
--- a/cc/trees/thread_proxy.h
+++ b/cc/trees/thread_proxy.h
@@ -82,11 +82,13 @@ class ThreadProxy : public Proxy,
   virtual void DidSwapBuffersCompleteOnImplThread() OVERRIDE;
   virtual void OnCanDrawStateChanged(bool can_draw) OVERRIDE;
   virtual void NotifyReadyToActivate() OVERRIDE;
-  // Please call these 2 functions through
-  // LayerTreeHostImpl's SetNeedsRedraw() and SetNeedsRedrawRect().
+  // Please call these 3 functions through
+  // LayerTreeHostImpl's SetNeedsRedraw(), SetNeedsRedrawRect() and
+  // SetNeedsAnimate().
   virtual void SetNeedsRedrawOnImplThread() OVERRIDE;
   virtual void SetNeedsRedrawRectOnImplThread(const gfx::Rect& dirty_rect)
       OVERRIDE;
+  virtual void SetNeedsAnimateOnImplThread() OVERRIDE;
   virtual void SetNeedsManageTilesOnImplThread() OVERRIDE;
   virtual void DidInitializeVisibleTileOnImplThread() OVERRIDE;
   virtual void SetNeedsCommitOnImplThread() OVERRIDE;
@@ -111,6 +113,7 @@ class ThreadProxy : public Proxy,
       OVERRIDE;
   virtual DrawSwapReadbackResult ScheduledActionDrawAndSwapForced() OVERRIDE;
   virtual DrawSwapReadbackResult ScheduledActionDrawAndReadback() OVERRIDE;
+  virtual void ScheduledActionAnimate() OVERRIDE;
   virtual void ScheduledActionCommit() OVERRIDE;
   virtual void ScheduledActionUpdateVisibleTiles() OVERRIDE;
   virtual void ScheduledActionActivatePendingTree() OVERRIDE;
@@ -283,7 +286,11 @@ class ThreadProxy : public Proxy,
 
     // Set when we freeze animations to avoid checkerboarding.
     bool animations_frozen_until_next_draw;
-    base::TimeTicks animation_freeze_time;
+    base::TimeTicks animation_time;
+
+    // Whether a commit has been completed since the last time animations were
+    // ticked. If this happens, we need to animate again.
+    bool did_commit_after_animating;
 
     base::TimeTicks smoothness_takes_priority_expiration_time;
     bool renew_tree_priority_pending;