Rename Animate as Begin(Main)Frame

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 2fa5b5880831ba9610aa7f35af5019d232ec4a0b..ae266b56b9f893b218c719db529c2268f8051af6 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -104,7 +104,7 @@ class CC_EXPORT LayerTreeHost {
     client_->WillBeginMainFrame(source_frame_number_);
   }
   void DidBeginMainFrame();
-  void UpdateClientAnimations(base::TimeTicks monotonic_frame_begin_time);
+  void BeginMainFrame(const BeginFrameArgs& args);
   void AnimateLayers(base::TimeTicks monotonic_frame_begin_time);
   void DidStopFlinging();
   void Layout();
@@ -361,7 +361,7 @@ class CC_EXPORT LayerTreeHost {
 
   void NotifySwapPromiseMonitorsOfSetNeedsCommit();
 
-  bool animating_;
+  bool inside_begin_main_frame_;
   bool needs_full_tree_sync_;
 
   base::CancelableClosure prepaint_callback_;