cc: DCHECK that the OutputSurface was released in ~LayerTreeHostImpl().

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 53020f0522d00a13ce9c9cc55e55929cfe1c0380..37883d0e62d1ed7c62696e94f1db1607d14da387 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -274,6 +274,9 @@ LayerTreeHostImpl::~LayerTreeHostImpl() {
   TRACE_EVENT_OBJECT_DELETED_WITH_ID(
       TRACE_DISABLED_BY_DEFAULT("cc.debug"), "cc::LayerTreeHostImpl", id_);
 
+  // It is released before shutdown.
+  DCHECK(!output_surface_);
+
   if (input_handler_client_) {
     input_handler_client_->WillShutdown();
     input_handler_client_ = NULL;
@@ -299,11 +302,6 @@ LayerTreeHostImpl::~LayerTreeHostImpl() {
   CleanUpTileManagerAndUIResources();
   renderer_ = nullptr;
   resource_provider_ = nullptr;
-
-  if (output_surface_) {
-    output_surface_->DetachFromClient();
-    output_surface_ = nullptr;
-  }
 }
 
 void LayerTreeHostImpl::BeginMainFrameAborted(CommitEarlyOutReason reason) {