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

cc/layers/layer_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 626 matching lines @@
     property_trees->changed = true;
     property_trees->effect_tree.set_needs_update(true);
   }
 }
 
 void LayerImpl::UpdatePropertyTreeForScrollingAndAnimationIfNeeded() {
   if (scrollable())
     UpdatePropertyTreeScrollOffset();
 
   if (HasAnyAnimationTargetingProperty(TargetProperty::TRANSFORM)) {
-    UpdatePropertyTreeTransform();
     UpdatePropertyTreeTransformIsAnimated(
         HasPotentiallyRunningTransformAnimation());
   }
 }
 
 gfx::ScrollOffset LayerImpl::ScrollOffsetForAnimation() const {
   return CurrentScrollOffset();
 }
 
 void LayerImpl::OnFilterAnimated(const FilterOperations& filters) {
@@ skipping 19 matching lines @@
   layer_tree_impl()->AddToOpacityAnimationsMap(id(), opacity);
 }
 
 void LayerImpl::OnTransformAnimated(const gfx::Transform& transform) {
   gfx::Transform old_transform = transform_;
   SetTransform(transform);
   UpdatePropertyTreeTransform();
   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();
   }
 }
 
 void LayerImpl::OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset) {
   // Only layers in the active tree should need to do anything here, since
   // layers in the pending tree will find out about these changes as a
   // result of the shared SyncedProperty.
   if (!IsActive())
     return;
@@ skipping 643 matching lines @@
            .layer_transforms_should_scale_layer_contents) {
     return default_scale;
   }
 
   gfx::Vector2dF transform_scales = MathUtil::ComputeTransform2dScaleComponents(
       ScreenSpaceTransform(), default_scale);
   return std::max(transform_scales.x(), transform_scales.y());
 }
 
 }  // namespace cc