Move context-related callbacks into OutputSurface

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index a500663336cfee853bb751abce136f043f9cf430..bfa05e39fa1d0f480db280aa7fe9a21f413508bc 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -990,6 +990,9 @@ void LayerTreeHostImpl::OnSendFrameToParentCompositorAck(
   // TODO(piman): We may need to do some validation on this ack before
   // processing it.
   renderer_->ReceiveCompositorFrameAck(ack);
+
+  // When using compositor frame data, the ack doubles as a swap complete ack.
+  OnSwapBuffersComplete();
 }
 
 void LayerTreeHostImpl::OnCanDrawStateChangedForTree() {
@@ -1149,7 +1152,11 @@ const LayerTreeSettings& LayerTreeHostImpl::Settings() const {
 }
 
 void LayerTreeHostImpl::DidLoseOutputSurface() {
-  client_->DidLoseOutputSurfaceOnImplThread();
+  // TODO(jamesr): The renderer_ check is needed to make some of the
+  // LayerTreeHostContextTest tests pass, but shouldn't be necessary (or
+  // important) in production. We should adjust the test to not need this.
+  if (renderer_)
+    client_->DidLoseOutputSurfaceOnImplThread();
 }
 
 void LayerTreeHostImpl::OnSwapBuffersComplete() {