cc: Clear entries from animations maps only when main thread wins

cc/trees/layer_tree_impl.cc

 // Copyright 2011 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/trees/layer_tree_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 587 matching lines @@
 
 void LayerTreeImpl::UpdatePropertyTreeScrollingAndAnimationFromMainThread() {
   // TODO(enne): This should get replaced by pulling out scrolling and
   // animations into their own trees.  Then scrolls and animations would have
   // their own ways of synchronizing across commits.  This occurs to push
   // updates from scrolling deltas on the compositor thread that have occurred
   // after begin frame and updates from animations that have ticked since begin
   // frame to a newly-committed property tree.
   if (layer_list_.empty())
     return;
+  std::vector<int> layer_ids_to_remove;
   for (auto& layer_id_to_opacity : opacity_animations_map_) {
     const int id = layer_id_to_opacity.first;
     if (property_trees_.IsInIdToIndexMap(PropertyTrees::TreeType::EFFECT, id)) {
       EffectNode* node = property_trees_.effect_tree.Node(
           property_trees_.effect_id_to_index_map[id]);
       if (!node->data.is_currently_animating_opacity ||
-          node->data.opacity == layer_id_to_opacity.second)
+          node->data.opacity == layer_id_to_opacity.second) {
+        layer_ids_to_remove.push_back(id);
         continue;
+      }
       node->data.opacity = layer_id_to_opacity.second;
       property_trees_.effect_tree.set_needs_update(true);
     }
   }
-  opacity_animations_map_.clear();
+  for (auto id : layer_ids_to_remove)
+    opacity_animations_map_.erase(id);
+  layer_ids_to_remove.clear();
 
   for (auto& layer_id_to_transform : transform_animations_map_) {
     const int id = layer_id_to_transform.first;
     if (property_trees_.IsInIdToIndexMap(PropertyTrees::TreeType::TRANSFORM,
                                          id)) {
       TransformNode* node = property_trees_.transform_tree.Node(
           property_trees_.transform_id_to_index_map[id]);
       if (!node->data.is_currently_animating ||
-          node->data.local == layer_id_to_transform.second)
+          node->data.local == layer_id_to_transform.second) {
+        layer_ids_to_remove.push_back(id);
         continue;
+      }
       node->data.local = layer_id_to_transform.second;
       node->data.needs_local_transform_update = true;
       property_trees_.transform_tree.set_needs_update(true);
     }
   }
-  transform_animations_map_.clear();
+  for (auto id : layer_ids_to_remove)
+    transform_animations_map_.erase(id);

[jaydasika, 2016/06/30 00:26:39]

Just realized map entries should be erased in RemoveLayer too. 

[jaydasika, 2016/06/30 18:52:00]

Done.

 
   LayerTreeHostCommon::CallFunctionForEveryLayer(this, [](LayerImpl* layer) {
     layer->UpdatePropertyTreeForScrollingAndAnimationIfNeeded();
   });
 }
 
 void LayerTreeImpl::SetPageScaleOnActiveTree(float active_page_scale) {
   DCHECK(IsActiveTree());
   if (page_scale_factor()->SetCurrent(
           ClampPageScaleFactorToLimits(active_page_scale))) {
@@ skipping 1444 matching lines @@
 
 void LayerTreeImpl::ResetAllChangeTracking() {
   layers_that_should_push_properties_.clear();
   // Iterate over all layers, including masks and replicas.
   for (auto& layer : *layers_)
     layer->ResetChangeTracking();
   property_trees_.ResetAllChangeTracking();
 }
 
 }  // namespace cc