cc : Use transform node data to determine which transform wins at commit

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 1f09776d36c15e72ee3dbbda3c76b37808c57ba0..979dbcc793997229b939dd0fc3271ad0e7e260f3 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -644,7 +644,6 @@ void LayerImpl::UpdatePropertyTreeForScrollingAndAnimationIfNeeded() {
     UpdatePropertyTreeScrollOffset();
 
   if (HasAnyAnimationTargetingProperty(TargetProperty::TRANSFORM)) {
-    UpdatePropertyTreeTransform();
     UpdatePropertyTreeTransformIsAnimated(
         HasPotentiallyRunningTransformAnimation());
   }
@@ -684,6 +683,7 @@ void LayerImpl::OnTransformAnimated(const gfx::Transform& transform) {
   was_ever_ready_since_last_transform_animation_ = false;
   if (old_transform != transform) {
     SetNeedsPushProperties();
+    layer_tree_impl()->AddToTransformAnimationsMap(id(), transform);

[ajuma, 2016/06/01 15:14:55]

I think this needs to happen even when old_transform == transform (just like we
do for opacity), since the old_transform might have been set before the last
commit (that is, the map might have been cleared since then, so if we skip this
step the map won't have a value for this id even though the animation is still
in progress). Please also include this case in the test you added.

[jaydasika, 2016/06/01 16:29:09]

Done.

     layer_tree_impl()->set_needs_update_draw_properties();
   }
 }