Use WebKit compositor in ui::Layer

ui/gfx/compositor/test_compositor_host_linux.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 "ui/gfx/compositor/test_compositor_host.h"
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "ui/base/x/x11_util.h"
@@ skipping 72 matching lines @@
       break;
   }
   compositor_ = ui::Compositor::Create(this, window_, bounds_.size());
 }
 
 ui::Compositor* TestCompositorHostLinux::GetCompositor() {
   return compositor_;
 }
 
 void TestCompositorHostLinux::ScheduleDraw() {
-  compositor_->Draw(false);
+  if (compositor_)
+    compositor_->Draw(false);
 }
 
 #if defined(TOUCH_UI) || defined(USE_AURA)
 base::MessagePumpDispatcher::DispatchStatus TestCompositorHostLinux::Dispatch(
     XEvent* xev) {
   return MessagePumpDispatcher::EVENT_IGNORED;
 }
 #elif defined(TOOLKIT_USES_GTK)
 bool TestCompositorHostLinux::Dispatch(GdkEvent*) {
   return false;
 }
 #endif
 
 // static
 TestCompositorHost* TestCompositorHost::Create(const gfx::Rect& bounds) {
   return new TestCompositorHostLinux(bounds);
 }
 
 }  // namespace ui