DirectCompositorFrameSink Uses CompositorFrameSinkSupport

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 <queue>
@@ skipping 70 matching lines @@
                                          std::vector<uint32_t>* sequence) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_EQ(lifetime_type_, LifetimeType::SEQUENCES);
   for (uint32_t value : *sequence)
     satisfied_sequences_.insert(SurfaceSequence(frame_sink_id, value));
   sequence->clear();
   GarbageCollectSurfaces();
 }
 
 void SurfaceManager::RegisterFrameSinkId(const FrameSinkId& frame_sink_id) {
-  bool inserted = valid_frame_sink_ids_.insert(frame_sink_id).second;
-  DCHECK(inserted);
+  valid_frame_sink_ids_.insert(frame_sink_id);

[jbauman, 2017/01/07 01:17:26]

Why is removing this DCHECK necessary? We shouldn't be registering the same
frame sink twice.

[Alex Z., 2017/01/07 14:35:49]

Originally, DirectCompositorFrameSink::BindToClient() doesn't call 
RegisterFrameSinkId(). CompositorFrameSinkSupport calls RegisterFrameSinkId() 
in its constructor, which triggers the DCHECK for DirectCompositorFrameSink.

fsamuel told me to remove the DCHECK instead of exposing RegisterFrameSinkId()
to GpuCompositorFrameSink or make a custom CompositorFrameSink() for 
DirectCompositorFrameSink.

[Fady Samuel, 2017/01/08 16:36:32]

ui::Compositor Registers the FrameSinkId first:
https://cs.chromium.org/chromium/src/ui/compositor/compositor.cc?sq=package:c...

However, we eventually want to get rid of that in favor of the SurfaceReference
approach to reference tracking. We're not there yet. For the time being, we are
registering the FrameSinkId in CompositorFrameSinkSupport. However, while we're
using SurfaceSequences, we cannot get rid of RegisterFrameSinkId in
ui::Compositor, so I thought getting rid of the DCHECK would be easier for now.

Note that once SurfaceReferences are used everywhere, RegisterFrameSinkId and
InvalidateFrameSinkId will likely go away.

 }
 
 void SurfaceManager::InvalidateFrameSinkId(const FrameSinkId& frame_sink_id) {
   valid_frame_sink_ids_.erase(frame_sink_id);
   GarbageCollectSurfaces();
 }
 
 const SurfaceId& SurfaceManager::GetRootSurfaceId() const {
   return root_surface_id_;
 }
@@ skipping 392 matching lines @@
   return changed;
 }
 
 void SurfaceManager::SurfaceCreated(const SurfaceInfo& surface_info) {
   CHECK(thread_checker_.CalledOnValidThread());
   for (auto& observer : observer_list_)
     observer.OnSurfaceCreated(surface_info);
 }
 
 }  // namespace cc