CC Animation: Introduce some dirty flags to optimize PushProperties on commit

cc/animation/scroll_offset_animations.cc

Index: cc/animation/scroll_offset_animations.cc
diff --git a/cc/animation/scroll_offset_animations.cc b/cc/animation/scroll_offset_animations.cc
index 04cf954c6f27ad286dafc83fb3f076a9c81c338c..3998c89a8db44388fe152823863d3d82201168fc 100644
--- a/cc/animation/scroll_offset_animations.cc
+++ b/cc/animation/scroll_offset_animations.cc
@@ -34,6 +34,7 @@ void ScrollOffsetAnimations::AddAdjustmentUpdate(ElementId element_id,
   update.adjustment_ += adjustment;
   element_to_update_map_[element_id] = update;
   animation_host_->SetNeedsCommit();
+  animation_host_->SetNeedsPushProperties();
 }
 
 void ScrollOffsetAnimations::AddTakeoverUpdate(ElementId element_id) {
@@ -42,6 +43,7 @@ void ScrollOffsetAnimations::AddTakeoverUpdate(ElementId element_id) {
   update.takeover_ = true;
   element_to_update_map_[element_id] = update;
   animation_host_->SetNeedsCommit();
+  animation_host_->SetNeedsPushProperties();
 }
 
 bool ScrollOffsetAnimations::HasUpdatesForTesting() const {