CompositorFrameSinkSupport should return resources before sending an ack

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 <algorithm>
 #include <utility>
 
 #include "cc/output/compositor_frame.h"
@@ skipping 116 matching lines @@
   SurfaceReference reference(surface_manager_->GetRootSurfaceId(), surface_id);
   surface_manager_->RemoveSurfaceReferences({reference});
 }
 
 void CompositorFrameSinkSupport::DidReceiveCompositorFrameAck() {
   DCHECK_GT(ack_pending_count_, 0);
   ack_pending_count_--;
 
   if (!client_)
     return;
-  client_->DidReceiveCompositorFrameAck();
+
+  // We return the resources before sending an ack so they can be reused in
+  // making the next CompositorFrame.
   if (!surface_returned_resources_.empty()) {
     client_->ReclaimResources(surface_returned_resources_);
     surface_returned_resources_.clear();
   }
+  client_->DidReceiveCompositorFrameAck();
 }
 
 void CompositorFrameSinkSupport::ForceReclaimResources() {
   surface_factory_.ClearSurface();
 }
 
 void CompositorFrameSinkSupport::ClaimTemporaryReference(
     const SurfaceId& surface_id) {
   surface_manager_->AssignTemporaryReference(surface_id, frame_sink_id_);
 }
@@ skipping 76 matching lines @@
   else
     begin_frame_source_->RemoveObserver(this);
 }
 
 void CompositorFrameSinkSupport::RequestCopyOfSurface(
     std::unique_ptr<CopyOutputRequest> request) {
   surface_factory_.RequestCopyOfSurface(std::move(request));
 }
 
 }  // namespace cc