Introduce Property Trees

cc/trees/layer_tree_host_common.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_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/base/math_util.h"
@@ skipping 2400 matching lines @@
       &accumulated_surface_state,
       inputs->current_render_surface_layer_list_id);
 
   // The dummy layer list should not have been used.
   DCHECK_EQ(0u, dummy_layer_list.size());
   // A root layer render_surface should always exist after
   // CalculateDrawProperties.
   DCHECK(inputs->root_layer->render_surface());
 
   // Now compare with the new approach.
-  OpacityTree opacity_tree;
-  TransformTree transform_tree;
-  ClipTree clip_tree;
+  // TODO(ajuma): Can we efficiently cache some of this rather than
+  // starting from scratch every frame?
+  OpacityTree opacity_tree(inputs->root_layer);
+  TransformTree transform_tree(inputs->root_layer);
+  ClipTree clip_tree(inputs->root_layer);
   ComputeVisibleRectsUsingPropertyTrees(inputs->root_layer,
                                         inputs->page_scale_application_layer,
                                         inputs->page_scale_factor,
                                         inputs->device_scale_factor,
                                         gfx::Rect(inputs->device_viewport_size),
                                         inputs->device_transform,
                                         &opacity_tree,
                                         &transform_tree,
                                         &clip_tree);
 
@@ skipping 82 matching lines @@
       inputs->current_render_surface_layer_list_id);
 
   // The dummy layer list should not have been used.
   DCHECK_EQ(0u, dummy_layer_list.size());
   // A root layer render_surface should always exist after
   // CalculateDrawProperties.
   DCHECK(inputs->root_layer->render_surface());
 }
 
 }  // namespace cc