Build mapping from element id to transform/effect nodes.

cc/trees/property_tree_builder.cc

 // Copyright 2014 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/property_tree_builder.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <set>
@@ skipping 604 matching lines @@
 
   data_for_children->property_trees->transform_tree.Insert(TransformNode(),
                                                            parent_index);
 
   TransformNode* node =
       data_for_children->property_trees->transform_tree.back();
   layer->SetTransformTreeIndex(node->id);
   data_for_children->property_trees->transform_id_to_index_map[layer->id()] =
       node->id;
 
+  // For animation subsystem purposes, if this layer has a compositor element
+  // id, we build a map from that id to this transform node.
+  if (layer->element_id()) {
+    data_for_children->property_trees
+        ->element_id_to_transform_node_index[layer->element_id()] = node->id;
+  }
+
   node->scrolls = is_scrollable;
   node->should_be_snapped = is_snapped;
   node->flattens_inherited_transform = data_for_children->should_flatten;
 
   node->sorting_context_id = SortingContextId(layer);
 
   if (layer == data_from_ancestor.page_scale_layer)
     data_for_children->in_subtree_of_page_scale_layer = true;
   node->in_subtree_of_page_scale_layer =
       data_for_children->in_subtree_of_page_scale_layer;
@@ skipping 453 matching lines @@
     // to root render surface's content, but not root render surface itself.
     node.transform_id = kRootPropertyTreeNodeId;
     node.clip_id = kViewportClipTreeNodeId;
   }
   data_for_children->effect_tree_parent = effect_tree.Insert(node, parent_id);
   int node_id = data_for_children->effect_tree_parent;
   layer->SetEffectTreeIndex(node_id);
   data_for_children->property_trees->effect_id_to_index_map[layer->id()] =
       data_for_children->effect_tree_parent;
 
+  // For animation subsystem purposes, if this layer has a compositor element
+  // id, we build a map from that id to this effect node.
+  if (layer->element_id()) {
+    data_for_children->property_trees
+        ->element_id_to_effect_node_index[layer->element_id()] = node_id;
+  }
+
   std::vector<std::unique_ptr<CopyOutputRequest>> layer_copy_requests;
   TakeCopyRequests(layer, &layer_copy_requests);
   for (auto& it : layer_copy_requests) {
     effect_tree.AddCopyRequest(node_id, std::move(it));
   }
   layer_copy_requests.clear();
 
   if (should_create_render_surface) {
     data_for_children->compound_transform_since_render_target =
         gfx::Transform();
@@ skipping 409 matching lines @@
     color = SkColorSetA(color, 255);
   BuildPropertyTreesTopLevelInternal(
       root_layer, page_scale_layer, inner_viewport_scroll_layer,
       outer_viewport_scroll_layer, overscroll_elasticity_layer,
       elastic_overscroll, page_scale_factor, device_scale_factor, viewport,
       device_transform, property_trees, color);
   property_trees->ResetCachedData();
 }
 
 }  // namespace cc