cc: Setup API to release OutputSurface from LTHClient.

cc/trees/single_thread_proxy.cc

 // Copyright 2011 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/trees/single_thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
@@ skipping 131 matching lines @@
 void SingleThreadProxy::RequestNewOutputSurface() {
   DCHECK(Proxy::IsMainThread());
   DCHECK(layer_tree_host_->output_surface_lost());
   output_surface_creation_callback_.Cancel();
   if (output_surface_creation_requested_)
     return;
   output_surface_creation_requested_ = true;
   layer_tree_host_->RequestNewOutputSurface();
 }
 
+scoped_ptr<OutputSurface> SingleThreadProxy::GetOutputSurface() {

[no sievers, 2015/09/10 00:00:22]

if (scheduler_on_impl_thread_)
  scheduler_on_impl_thread_->DidLoseOutputSurface();

You can argue over whether the scheduler should trigger a
RequestNewOutputSurface() or not after you become visible again, but I think you
still need to clear some other state in the scheduler regardless which this
should take care of.

[sohanjg, 2015/09/10 15:07:23]

Done.

+  return layer_tree_host_impl_->GetOutputSurface();
+}
+
 void SingleThreadProxy::SetOutputSurface(
     scoped_ptr<OutputSurface> output_surface) {
   DCHECK(Proxy::IsMainThread());
   DCHECK(layer_tree_host_->output_surface_lost());
   DCHECK(output_surface_creation_requested_);
   renderer_capabilities_for_main_thread_ = RendererCapabilities();
 
   bool success;
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
@@ skipping 758 matching lines @@
       << "DidFinishImplFrame called while not inside an impl frame!";
   inside_impl_frame_ = false;
 #endif
 }
 
 void SingleThreadProxy::SendBeginFramesToChildren(const BeginFrameArgs& args) {
   layer_tree_host_->SendBeginFramesToChildren(args);
 }
 
 }  // namespace cc