Add DisplayCompositorTest.

cc/surfaces/surface_manager.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_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 72 matching lines @@
 void SurfaceManager::RegisterFrameSinkId(const FrameSinkId& frame_sink_id) {
   bool inserted = valid_frame_sink_ids_.insert(frame_sink_id).second;
   DCHECK(inserted);
 }
 
 void SurfaceManager::InvalidateFrameSinkId(const FrameSinkId& frame_sink_id) {
   valid_frame_sink_ids_.erase(frame_sink_id);
   GarbageCollectSurfaces();
 }
 
+const SurfaceId& SurfaceManager::GetRootSurfaceId() const {
+  return kRootSurfaceId;
+}
+
 void SurfaceManager::AddSurfaceReference(const SurfaceId& parent_id,
                                          const SurfaceId& child_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Check some conditions that should never happen. We don't want to crash on
   // bad input from a compromised client so just return early.
   if (parent_id == child_id) {
     LOG(ERROR) << "Cannot add self reference for " << parent_id.ToString();
     return;
   }
@@ skipping 335 matching lines @@
 
 void SurfaceManager::SurfaceCreated(const SurfaceId& surface_id,
                                     const gfx::Size& frame_size,
                                     float device_scale_factor) {
   CHECK(thread_checker_.CalledOnValidThread());
   for (auto& observer : observer_list_)
     observer.OnSurfaceCreated(surface_id, frame_size, device_scale_factor);
 }
 
 }  // namespace cc