compositor-worker: Introduce WebCompositorMutableState

cc/trees/layer_tree_impl.h

 // Copyright 2012 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.
 
 #ifndef CC_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
-#include <stddef.h>
-#include <stdint.h>
-
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/values.h"
 #include "cc/base/synced_property.h"
 #include "cc/input/layer_selection_bound.h"
@@ skipping 113 matching lines @@
   void SetPropertyTrees(const PropertyTrees& property_trees) {
     property_trees_ = property_trees;
     property_trees_.transform_tree.set_source_to_parent_updates_allowed(false);
   }
   PropertyTrees* property_trees() { return &property_trees_; }
 
   void UpdatePropertyTreesForBoundsDelta();
 
   void PushPropertiesTo(LayerTreeImpl* tree_impl);
 
+  struct CC_EXPORT ElementLayers {
+    // Transform and opacity mutations apply to this layer.
+    LayerImpl* main = nullptr;
+    // Scroll mutations apply to this layer.
+    LayerImpl* scroll = nullptr;
+  };
+
+  void AddToElementMap(LayerImpl* layer);
+  void RemoveFromElementMap(LayerImpl* layer);
+  ElementLayers GetMutableLayers(uint64_t element_id);
   int source_frame_number() const { return source_frame_number_; }
   void set_source_frame_number(int frame_number) {
     source_frame_number_ = frame_number;
   }
 
   bool is_first_frame_after_commit() const {
     return source_frame_number_ != is_first_frame_after_commit_tracker_;
   }
 
   void set_is_first_frame_after_commit(bool is_first_frame_after_commit) {
@@ skipping 315 matching lines @@
   float max_page_scale_factor_;
 
   float device_scale_factor_;
   float painted_device_scale_factor_;
 
   scoped_refptr<SyncedElasticOverscroll> elastic_overscroll_;
 
   typedef base::hash_map<int, LayerImpl*> LayerIdMap;
   LayerIdMap layer_id_map_;
 
+  base::hash_map<uint64_t, ElementLayers> element_layers_map_;
+
   // Maps from clip layer ids to scroll layer ids.  Note that this only includes
   // the subset of clip layers that act as scrolling containers.  (This is
   // derived from LayerImpl::scroll_clip_layer_ and exists to avoid O(n) walks.)
   base::hash_map<int, int> clip_scroll_map_;
 
   // Maps scroll layer ids to scrollbar layer ids.  For each scroll layer, there
   // may be 1 or 2 scrollbar layers (for vertical and horizontal).  (This is
   // derived from ScrollbarLayerImplBase::scroll_layer_id_ and exists to avoid
   // O(n) walks.)
   std::multimap<int, int> scrollbar_map_;
@@ skipping 38 matching lines @@
 
   scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_