cc : Push layer lists instead of layer tree at commit and activation

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index ff7a4f84256627fbcbcc63b5e1131fa6944f2572..2b0e4a473f17c8ef7007524372da697ebb7c829a 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -135,6 +135,7 @@ class CC_EXPORT LayerTreeImpl {
   // ---------------------------------------------------------------------------
   LayerImpl* root_layer() const { return root_layer_; }
   void SetRootLayer(std::unique_ptr<LayerImpl>);
+  void SetRootLayerFromLayerList();
   bool IsRootLayer(const LayerImpl* layer) const;
   std::unique_ptr<OwnedLayerImplList> DetachLayers();
 
@@ -147,10 +148,10 @@ class CC_EXPORT LayerTreeImpl {
 
   void MoveChangeTrackingToLayers();
 
-  LayerListIterator<LayerImpl> begin() const;
-  LayerListIterator<LayerImpl> end() const;
-  LayerListReverseIterator<LayerImpl> rbegin();
-  LayerListReverseIterator<LayerImpl> rend();
+  std::vector<LayerImpl*>::const_iterator begin() const;
+  std::vector<LayerImpl*>::const_iterator end() const;
+  std::vector<LayerImpl*>::reverse_iterator rbegin();
+  std::vector<LayerImpl*>::reverse_iterator rend();

[ajuma, 2016/06/09 15:15:19]

There's a LayerImplList type defined (as vector<LayerImpl*>) in
layer_collections.h. Should we use that here? (Also as the type of layer_list_.)

[jaydasika, 2016/06/09 16:56:25]

Done.

 
   struct CC_EXPORT ElementLayers {
     // Transform and opacity mutations apply to this layer.
@@ -474,6 +475,12 @@ class CC_EXPORT LayerTreeImpl {
 
   void ResetAllChangeTracking();
 
+  void AddToLayerList(LayerImpl* layer);
+
+  void ClearLayerList();
+
+  void BuildLayerListForTesting();
+
  protected:
   explicit LayerTreeImpl(
       LayerTreeHostImpl* layer_tree_host_impl,
@@ -579,7 +586,6 @@ class CC_EXPORT LayerTreeImpl {
   std::unique_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
-  void BuildLayerListForTesting();
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };