cc: Get rid of PostSwapBuffersComplete.

blimp/client/core/compositor/blimp_compositor.cc

Index: blimp/client/core/compositor/blimp_compositor.cc
diff --git a/blimp/client/core/compositor/blimp_compositor.cc b/blimp/client/core/compositor/blimp_compositor.cc
index 0ac6944f9b496aba9a4aa3cdb8091343b7eb03ce..e7ebe2c25e5ae54fd01fa70a4cc953898cc204e8 100644
--- a/blimp/client/core/compositor/blimp_compositor.cc
+++ b/blimp/client/core/compositor/blimp_compositor.cc
@@ -243,8 +243,18 @@ void BlimpCompositor::SwapCompositorFrame(cc::CompositorFrame frame) {
     layer_->AddChild(content_layer);
   }
 
-  surface_factory_->SubmitCompositorFrame(local_frame_id_, std::move(frame),
-                                          base::Closure());
+  surface_factory_->SubmitCompositorFrame(
+      local_frame_id_, std::move(frame),
+      base::Bind(&BlimpCompositor::SubmitCompositorFrameAck,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void BlimpCompositor::SubmitCompositorFrameAck() {
+  DCHECK(surface_factory_);

[danakj, 2016/10/08 02:05:44]

I cargo-culted this, but is it value?

[Khushal, 2016/10/10 17:40:10]

The aim was to assert that these calls should come only when we are bound to a
CompositorFrameSink, which is what the lifetime of SurfaceFactory is tied to.

[enne (OOO), 2016/10/10 20:42:20]

I'm not sure what the point of this is.  If this method just posts a task, then
this DCHECK doesn't really say anything about the state of surface factory when
that task runs.

[danakj, 2016/10/10 20:46:36]

I think DCHECKing proxy_client_ is not null would give the same information but
make it more clear what/why it's checking. WDYT?

[danakj, 2016/10/10 20:48:12]

No that seems incorrect actually, cuz proxy_client_ is a weak ptr so it can
become null suddenly.

+  compositor_dependencies_->GetCompositorTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&BlimpCompositorFrameSinkProxyClient::SwapCompositorFrameAck,
+                 proxy_client_));
 }
 
 void BlimpCompositor::UnbindProxyClient() {