First draft to enable turning off compositor for unit tests.

views/widget/widget.cc

 // Copyright (c) 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 "views/widget/widget.h"
 
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "ui/gfx/compositor/compositor.h"
 #include "views/focus/view_storage.h"
@@ skipping 616 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // Widget, private:
 
 void Widget::EnsureCompositor() {
   DCHECK(!compositor_.get());
 
   // TODO(sad): If there is a parent Widget, then use the same compositor
   //            instead of creating a new one here.
   gfx::AcceleratedWidget widget = native_widget_->GetAcceleratedWidget();
-  if (widget != gfx::kNullAcceleratedWidget)
+  if (widget != gfx::kNullAcceleratedWidget &&
+                View::get_use_acceleration_when_possible())
     compositor_ = ui::Compositor::Create(widget);
 }
 
 bool Widget::ShouldReleaseCaptureOnMouseReleased() const {
   return true;
 }
 
 }  // namespace views