cc: refcount resources as we send them to the parent

cc/layers/delegated_renderer_layer.cc

 // 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.
 
 #include "cc/layers/delegated_renderer_layer.h"
 
 #include "cc/layers/delegated_renderer_layer_client.h"
 #include "cc/layers/delegated_renderer_layer_impl.h"
 #include "cc/output/delegated_frame_data.h"
 
@@ skipping 50 matching lines @@
 void DelegatedRendererLayer::SetDisplaySize(gfx::Size size) {
   if (display_size_ == size)
     return;
   display_size_ = size;
   SetNeedsCommit();
 }
 
 void DelegatedRendererLayer::SetFrameData(
     scoped_ptr<DelegatedFrameData> new_frame_data) {
   if (frame_data_) {
-    // Copy the resources from the last provided frame into the new frame, as
-    // it may use resources that were transferred in the last frame.
-    new_frame_data->resource_list.insert(new_frame_data->resource_list.end(),
-                                         frame_data_->resource_list.begin(),
-                                         frame_data_->resource_list.end());
+    // Copy the resources from the last provided frame into the unused resources
+    // list, as the new frame will provide its own resources.
+    unused_resources_for_child_compositor_.insert(
+        unused_resources_for_child_compositor_.end(),
+        frame_data_->resource_list.begin(),
+        frame_data_->resource_list.end());
   }
   frame_data_ = new_frame_data.Pass();
   if (!frame_data_->render_pass_list.empty()) {
     RenderPass* root_pass = frame_data_->render_pass_list.back();
     damage_in_frame_.Union(root_pass->damage_rect);
     frame_size_ = root_pass->output_rect.size();
-
-    // TODO(danakj): This could be optimized to only add resources to the
-    // frame_data_ if they are actually used in the frame. For now, it will
-    // cause the parent (this layer) to hold onto some resources it doesn't
-    // need to for an extra frame.
-    for (size_t i = 0; i < unused_resources_for_child_compositor_.size(); ++i) {
-      frame_data_->resource_list.push_back(
-          unused_resources_for_child_compositor_[i]);
-    }
-    unused_resources_for_child_compositor_.clear();
   } else {
     frame_size_ = gfx::Size();
   }
   SetNeedsCommit();
 }
 
 void DelegatedRendererLayer::TakeUnusedResourcesForChildCompositor(
     TransferableResourceArray* array) {
   DCHECK(array->empty());
   array->clear();
 
   array->swap(unused_resources_for_child_compositor_);
 }
 
 bool DelegatedRendererLayer::BlocksPendingCommit() const {
   // The active frame needs to be replaced and resources returned before the
   // commit is called complete. This is true even whenever there may be
   // resources to return, regardless of if the layer will draw in its new
   // state.
   return true;
 }
 
 }  // namespace cc