Add Satisfy() and Require() to MojoCompositorFrameSink

cc/surfaces/compositor_frame_sink_support.cc

 // Copyright 2016 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/compositor_frame_sink_support.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/compositor_frame_sink_support_client.h"
 #include "cc/surfaces/display.h"
+#include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_manager.h"
 
 namespace cc {
 
 CompositorFrameSinkSupport::CompositorFrameSinkSupport(
     CompositorFrameSinkSupportClient* client,
     SurfaceManager* surface_manager,
     const FrameSinkId& frame_sink_id,
     std::unique_ptr<Display> display)
     : client_(client),
@@ skipping 50 matching lines @@
   surface_factory_.SubmitCompositorFrame(
       local_frame_id_, std::move(frame),
       base::Bind(&CompositorFrameSinkSupport::DidReceiveCompositorFrameAck,
                  weak_factory_.GetWeakPtr()));
   if (display_) {
     display_->SetLocalFrameId(local_frame_id_,
                               frame.metadata.device_scale_factor);
   }
 }
 
+void CompositorFrameSinkSupport::Require(const LocalFrameId& local_frame_id,
+                                         const SurfaceSequence& sequence) {
+  Surface* surface = surface_manager_->GetSurfaceForId(
+      SurfaceId(frame_sink_id_, local_frame_id));
+  DCHECK(surface);  // Ensure the surface exists before requiring callback

[Fady Samuel, 2016/12/06 16:45:25]

nit: How about this comment? 

If this fails then that implies that a client is trying to reference a surface
that no longer exists. This could result in flicker or missing components of UI.

[Alex Z., 2016/12/06 16:55:40]

Done.

+  surface->AddDestructionDependency(sequence);
+}
+
+void CompositorFrameSinkSupport::Satisfy(const SurfaceSequence& sequence) {
+  std::vector<uint32_t> sequences = {sequence.sequence};
+  surface_manager_->DidSatisfySequences(sequence.frame_sink_id, &sequences);
+}
+
 void CompositorFrameSinkSupport::DidReceiveCompositorFrameAck() {
   DCHECK_GT(ack_pending_count_, 0);
   ack_pending_count_--;
 
   if (!client_)
     return;
   client_->DidReceiveCompositorFrameAck();
   if (!surface_returned_resources_.empty()) {
     client_->ReclaimResources(surface_returned_resources_);
     surface_returned_resources_.clear();
@@ skipping 73 matching lines @@
     return;
 
   added_frame_observer_ = needs_begin_frame_;
   if (needs_begin_frame_)
     begin_frame_source_->AddObserver(this);
   else
     begin_frame_source_->RemoveObserver(this);
 }
 
 }  // namespace cc