cc: Compute RenderSurfaceImpl's TransformTreeIndex using its effect node

cc/trees/property_tree.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 <stddef.h>
 
 #include <set>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 31 matching lines @@
 
 template <typename T>
 PropertyTree<T>& PropertyTree<T>::operator=(const PropertyTree<T>&) = default;
 
 TransformTree::TransformTree()
     : source_to_parent_updates_allowed_(true),
       page_scale_factor_(1.f),
       device_scale_factor_(1.f),
       device_transform_scale_factor_(1.f) {
   cached_data_.push_back(TransformCachedNodeData());
+  cached_data_[kRootNodeId].target_id = kRootNodeId;
 }
 
 TransformTree::~TransformTree() = default;
 TransformTree& TransformTree::operator=(const TransformTree&) = default;
 
 template <typename T>
 int PropertyTree<T>::Insert(const T& tree_node, int parent_id) {
   DCHECK_GT(nodes_.size(), 0u);
   nodes_.push_back(tree_node);
   T& node = nodes_.back();
@@ skipping 48 matching lines @@
 void TransformTree::clear() {
   PropertyTree<TransformNode>::clear();
 
   page_scale_factor_ = 1.f;
   device_scale_factor_ = 1.f;
   device_transform_scale_factor_ = 1.f;
   nodes_affected_by_inner_viewport_bounds_delta_.clear();
   nodes_affected_by_outer_viewport_bounds_delta_.clear();
   cached_data_.clear();
   cached_data_.push_back(TransformCachedNodeData());
+  cached_data_[kRootNodeId].target_id = kRootNodeId;
   sticky_position_data_.clear();
 
 #if DCHECK_IS_ON()
   TransformTree tree;
   // TODO(jaydasika) : Move tests that expect source_to_parent_updates_allowed
   // to be true on impl thread to main thread and set it to is_main_thread here.
   tree.source_to_parent_updates_allowed_ = source_to_parent_updates_allowed_;
   DCHECK(tree == *this);
 #endif
 }
@@ skipping 1929 matching lines @@
       transform_tree.nodes().size(), std::vector<DrawTransformData>(1));
 }
 
 void PropertyTrees::UpdateCachedNumber() {
   cached_data_.property_tree_update_number++;
 }
 
 gfx::Transform PropertyTrees::ToScreenSpaceTransformWithoutSurfaceContentsScale(
     int transform_id,
     int effect_id) const {
-  DCHECK_GT(transform_id, 0);
-  if (transform_id == 1) {
+  if (transform_id == TransformTree::kRootNodeId) {
     return gfx::Transform();
   }
   gfx::Transform screen_space_transform = transform_tree.ToScreen(transform_id);
   const EffectNode* effect_node = effect_tree.Node(effect_id);
 
   if (effect_node->surface_contents_scale.x() != 0.0 &&
       effect_node->surface_contents_scale.y() != 0.0)
     screen_space_transform.Scale(1.0 / effect_node->surface_contents_scale.x(),
                                  1.0 / effect_node->surface_contents_scale.y());
   return screen_space_transform;
 }
 
 bool PropertyTrees::ComputeTransformFromTarget(
     int transform_id,
     int effect_id,
     gfx::Transform* transform) const {
   transform->MakeIdentity();
   if (transform_id == TransformTree::kInvalidNodeId)
     return true;
 
   const EffectNode* effect_node = effect_tree.Node(effect_id);
 
   bool success = GetFromTarget(transform_id, effect_id, transform);
   transform->Scale(effect_node->surface_contents_scale.x(),
                    effect_node->surface_contents_scale.y());
   return success;
 }
 
 }  // namespace cc