Keep vsync enabled while there is a pending requestAnimationFrame

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 08da4add85cf8622c8c9081a1657a2ad60f3deb7..b83eab143ce6df751a0adcce83a07dcab2ca35b5 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -75,6 +75,8 @@ class CC_EXPORT Scheduler : FrameRateControllerClient {
 
   void SetMainThreadNeedsLayerTextures();
 
+  void SetAnimateRequested();
+
   // Like SetNeedsRedraw(), but ensures the draw will definitely happen even if
   // we are not visible.
   void SetNeedsForcedRedraw();