Aura: add a bench utility

ui/aura/root_window.cc

 // Copyright (c) 2012 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 "ui/aura/root_window.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 227 matching lines @@
   }
   if (compositor_lock_) {
     draw_on_compositor_unlock_ = true;
     defer_draw_scheduling_ = false;
     return;
   }
   waiting_on_compositing_end_ = true;
 
   TRACE_EVENT_ASYNC_BEGIN0("ui", "RootWindow::Draw", draw_trace_count_++);
 
+  defer_draw_scheduling_ = false;
   compositor_->Draw(false);
-  defer_draw_scheduling_ = false;
 }
 
 void RootWindow::ScheduleFullDraw() {
   compositor_->ScheduleFullDraw();
 }
 
 bool RootWindow::DispatchMouseEvent(MouseEvent* event) {
   if (mouse_move_hold_count_) {
     if (event->type() == ui::ET_MOUSE_DRAGGED ||
         (event->flags() & ui::EF_IS_SYNTHESIZED)) {
@@ skipping 777 matching lines @@
 void RootWindow::UnlockCompositor() {
   DCHECK(compositor_lock_);
   compositor_lock_ = NULL;
   if (draw_on_compositor_unlock_) {
     draw_on_compositor_unlock_ = false;
     ScheduleDraw();
   }
 }
 
 }  // namespace aura