Make cc::CompositorFrames movable [Part 2 of 2]

cc/surfaces/surface_aggregator.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/surfaces/surface_aggregator.h"
 
 #include <stddef.h>
 
 #include <map>
 
@@ skipping 752 matching lines @@
     if (it == render_pass_dependencies_.end())
       continue;
     for (auto pass : it->second) {
       if (copy_request_passes_.insert(pass).second) {
         copy_requests_to_iterate.push_back(pass);
       }
     }
   }
 }
 
-std::unique_ptr<CompositorFrame> SurfaceAggregator::Aggregate(
-    SurfaceId surface_id) {
+CompositorFrame SurfaceAggregator::Aggregate(SurfaceId surface_id) {
   Surface* surface = manager_->GetSurfaceForId(surface_id);
   DCHECK(surface);
   contained_surfaces_[surface_id] = surface->frame_index();
   const CompositorFrame* root_surface_frame = surface->GetEligibleFrame();
-  if (!root_surface_frame)
-    return nullptr;
+  if (!root_surface_frame->delegated_frame_data)
+    return CompositorFrame();
   TRACE_EVENT0("cc", "SurfaceAggregator::Aggregate");
 
-  std::unique_ptr<CompositorFrame> frame(new CompositorFrame);
-  frame->delegated_frame_data = base::WrapUnique(new DelegatedFrameData);
+  CompositorFrame frame;
+  frame.delegated_frame_data = base::WrapUnique(new DelegatedFrameData);
 
-  DCHECK(root_surface_frame->delegated_frame_data);
-
-  dest_resource_list_ = &frame->delegated_frame_data->resource_list;
-  dest_pass_list_ = &frame->delegated_frame_data->render_pass_list;
+  dest_resource_list_ = &frame.delegated_frame_data->resource_list;
+  dest_pass_list_ = &frame.delegated_frame_data->render_pass_list;
 
   valid_surfaces_.clear();
   PrewalkResult prewalk_result;
   root_damage_rect_ =
       PrewalkTree(surface_id, false, RenderPassId(), &prewalk_result);
   PropagateCopyRequestPasses();
   has_copy_requests_ = !copy_request_passes_.empty();
 
   CopyUndrawnSurfaces(&prewalk_result);
   SurfaceSet::iterator it = referenced_surfaces_.insert(surface_id).first;
   CopyPasses(root_surface_frame->delegated_frame_data.get(), surface);
   referenced_surfaces_.erase(it);
 
   moved_pixel_passes_.clear();
   copy_request_passes_.clear();
   render_pass_dependencies_.clear();
 
   DCHECK(referenced_surfaces_.empty());
 
   if (dest_pass_list_->empty())
-    return nullptr;
+    return CompositorFrame();
 
   dest_pass_list_ = NULL;
   ProcessAddedAndRemovedSurfaces();
   contained_surfaces_.swap(previous_contained_surfaces_);
   contained_surfaces_.clear();
 
   for (SurfaceIndexMap::iterator it = previous_contained_surfaces_.begin();
        it != previous_contained_surfaces_.end();
        ++it) {
     Surface* surface = manager_->GetSurfaceForId(it->first);
     if (surface)
-      surface->TakeLatencyInfo(&frame->metadata.latency_info);
+      surface->TakeLatencyInfo(&frame.metadata.latency_info);
   }
 
   // TODO(jamesr): Aggregate all resource references into the returned frame's
   // resource list.
 
   return frame;
 }
 
 void SurfaceAggregator::ReleaseResources(SurfaceId surface_id) {
   SurfaceToResourceChildIdMap::iterator it =
       surface_id_to_resource_child_id_.find(surface_id);
   if (it != surface_id_to_resource_child_id_.end()) {
     provider_->DestroyChild(it->second);
     surface_id_to_resource_child_id_.erase(it);
   }
 }
 
 void SurfaceAggregator::SetFullDamageForSurface(SurfaceId surface_id) {
   auto it = previous_contained_surfaces_.find(surface_id);
   if (it == previous_contained_surfaces_.end())
     return;
   // Set the last drawn index as 0 to ensure full damage next time it's drawn.
   it->second = 0;
 }
 
 }  // namespace cc