cc: Add mask and replica layer ids to the effect tree

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 73 matching lines @@
   property_trees()->is_main_thread = false;
 }
 
 LayerTreeImpl::~LayerTreeImpl() {
   BreakSwapPromises(IsActiveTree() ? SwapPromise::SWAP_FAILS
                                    : SwapPromise::ACTIVATION_FAILS);
 
   // Need to explicitly clear the tree prior to destroying this so that
   // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
   DCHECK(!root_layer_);
+  DCHECK(layers_->empty());
 }
 
 void LayerTreeImpl::Shutdown() {
   DetachLayers();
   DCHECK(!root_layer_);
 }
 
 void LayerTreeImpl::ReleaseResources() {
   if (root_layer_) {
     LayerTreeHostCommon::CallFunctionForEveryLayer(
@@ skipping 812 matching lines @@
       if (it.represents_contributing_render_surface()) {
         // Surfaces aren't used by the tile raster code, so they can have
         // occlusion regardless of replicas.
         Occlusion occlusion =
             occlusion_tracker.GetCurrentOcclusionForContributingSurface(
                 it->render_surface()->draw_transform());
         it->render_surface()->set_occlusion_in_content_space(occlusion);
         // Masks are used to draw the contributing surface, so should have
         // the same occlusion as the surface (nothing inside the surface
         // occludes them).
-        if (LayerImpl* mask = it->mask_layer()) {
+        if (LayerImpl* mask = it->render_surface()->MaskLayer()) {
           Occlusion mask_occlusion =
               inside_replica
                   ? Occlusion()
                   : occlusion_tracker.GetCurrentOcclusionForContributingSurface(
                         it->render_surface()->draw_transform() *
                         it->DrawTransform());
           mask->draw_properties().occlusion_in_content_space = mask_occlusion;
         }
-        if (LayerImpl* replica = it->replica_layer()) {
-          if (LayerImpl* mask = replica->mask_layer())
-            mask->draw_properties().occlusion_in_content_space = Occlusion();
+        if (LayerImpl* replica_mask =
+                it->render_surface()->ReplicaMaskLayer()) {
+          replica_mask->draw_properties().occlusion_in_content_space =
+              Occlusion();
         }
       }
 
       occlusion_tracker.LeaveLayer(it);
     }
 
     unoccluded_screen_space_region_ =
         occlusion_tracker.ComputeVisibleRegionInScreen(this);
   }
 
@@ skipping 78 matching lines @@
 
   gfx::SizeF content_size = root_scroll_layer->BoundsForScrolling();
   gfx::SizeF viewport_size =
       root_scroll_layer->scroll_clip_layer()->BoundsForScrolling();
 
   content_size.SetToMax(viewport_size);
   return content_size;
 }
 
 LayerImpl* LayerTreeImpl::LayerById(int id) const {
+  if (id == Layer::INVALID_ID)
+    return nullptr;

[jaydasika, 2016/06/14 06:12:06]

Is this required ? If we had invalid id, we would be returning nullptr in line
1041 below.

[ajuma, 2016/06/14 12:45:26]

Removed.

   LayerImplMap::const_iterator iter = layer_id_map_.find(id);
-  return iter != layer_id_map_.end() ? iter->second : NULL;
+  return iter != layer_id_map_.end() ? iter->second : nullptr;
 }
 
 void LayerTreeImpl::AddLayerShouldPushProperties(LayerImpl* layer) {
   layers_that_should_push_properties_.insert(layer);
 }
 
 void LayerTreeImpl::RemoveLayerShouldPushProperties(LayerImpl* layer) {
   layers_that_should_push_properties_.erase(layer);
 }
 
@@ skipping 1021 matching lines @@
       ->TransformAnimationBoundsForBox(layer->id(), box, bounds);
 }
 
 void LayerTreeImpl::ScrollAnimationAbort(bool needs_completion) {
   layer_tree_host_impl_->animation_host()->ScrollAnimationAbort(
       needs_completion);
 }
 
 void LayerTreeImpl::ResetAllChangeTracking() {
   layers_that_should_push_properties_.clear();
-  for (auto* layer : *this)
+  // Iterate over all layers, including masks and replicas.
+  for (auto& layer : *layers_)
     layer->ResetChangeTracking();
   property_trees_.ResetAllChangeTracking();
 }
 
 }  // namespace cc