Do SetNeedsCommit() instead of Composite() in threaded mode.

cc/trees/layer_tree_host.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/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 678 matching lines @@
   pending_page_scale_animation_->duration = duration;
 
   SetNeedsCommit();
 }
 
 void LayerTreeHost::NotifyInputThrottledUntilCommit() {
   proxy_->NotifyInputThrottledUntilCommit();
 }
 
 void LayerTreeHost::Composite(base::TimeTicks frame_begin_time) {
-  if (!proxy_->HasImplThread())
-    static_cast<SingleThreadProxy*>(proxy_.get())->CompositeImmediately(
-        frame_begin_time);
-  else
-    SetNeedsCommit();
+  DCHECK(!proxy_->HasImplThread());
+  SingleThreadProxy* proxy = static_cast<SingleThreadProxy*>(proxy_.get());
+  proxy->CompositeImmediately(frame_begin_time);
 }
 
 bool LayerTreeHost::InitializeOutputSurfaceIfNeeded() {
   if (!output_surface_can_be_initialized_)
     return false;
 
   if (output_surface_lost_)
     proxy_->CreateAndInitializeOutputSurface();
   return !output_surface_lost_;
 }
@@ skipping 538 matching lines @@
   swap_promise_list_.push_back(swap_promise.Pass());
 }
 
 void LayerTreeHost::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
   for (size_t i = 0; i < swap_promise_list_.size(); i++)
     swap_promise_list_[i]->DidNotSwap(reason);
   swap_promise_list_.clear();
 }
 
 }  // namespace cc