cc: Setup API to release OutputSurface from LTHClient.

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 9fac98bb3490af63272a63cdcee171987260f85d..d7eb38ce0d44d83be17fbda3678841e6c18b3b57 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -217,6 +217,18 @@ void ThreadProxy::SetOutputSurface(scoped_ptr<OutputSurface> output_surface) {
                  impl_thread_weak_ptr_, base::Passed(&output_surface)));
 }
 
+scoped_ptr<OutputSurface> ThreadProxy::ReleaseOutputSurface() {
+  DCHECK(IsMainThread());
+
+  DebugScopedSetMainThreadBlocked main_thread_blocked(this);
+  CompletionEvent completion;
+  Proxy::ImplThreadTaskRunner()->PostTask(
+      FROM_HERE, base::Bind(&ThreadProxy::ReleaseOutputSurfaceOnImplThread,
+                            impl_thread_weak_ptr_, &completion));
+  completion.Wait();
+  return output_surface_.Pass();

[no sievers, 2015/09/10 17:27:45]

You don't need this variable, but you can have a scoped_ptr<> on the stack here
and then pass a ptr to it to ReleaseOutputSurfaceOnImplThread().

[sohanjg, 2015/09/11 07:00:50]

Done.

+}
+
 void ThreadProxy::DidInitializeOutputSurface(
     bool success,
     const RendererCapabilities& capabilities) {
@@ -1082,6 +1094,16 @@ void ThreadProxy::InitializeOutputSurfaceOnImplThread(
     impl().scheduler->DidCreateAndInitializeOutputSurface();
 }
 
+void ThreadProxy::ReleaseOutputSurfaceOnImplThread(
+    CompletionEvent* completion) {
+  TRACE_EVENT0("cc", "ThreadProxy::FinishAllRenderingOnImplThread");

[no sievers, 2015/09/10 17:27:45]

nit: "ThreadProxy::ReleaseOutputSurfaceOnImplThread"

[sohanjg, 2015/09/11 07:00:50]

Done.

+  DCHECK(IsImplThread());
+
+  impl().scheduler->DidLoseOutputSurface();
+  output_surface_ = impl().layer_tree_host_impl->ReleaseOutputSurface();
+  completion->Signal();
+}
+
 void ThreadProxy::FinishGLOnImplThread(CompletionEvent* completion) {
   TRACE_EVENT0("cc", "ThreadProxy::FinishGLOnImplThread");
   DCHECK(IsImplThread());