Use a mocked compositor for unit tests

ui/aura/desktop.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/aura/desktop.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "ui/aura/desktop_delegate.h"
 #include "ui/aura/desktop_host.h"
 #include "ui/aura/desktop_observer.h"
 #include "ui/aura/event.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/screen_aura.h"
 #include "ui/aura/toplevel_window_container.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/gfx/compositor/compositor.h"
 #include "ui/gfx/compositor/layer.h"
 
 namespace aura {
 
 // static
 Desktop* Desktop::instance_ = NULL;
 
-// static
-ui::Compositor*(*Desktop::compositor_factory_)() = NULL;
-
 Desktop::Desktop()
     : delegate_(NULL),
       host_(aura::DesktopHost::Create(gfx::Rect(200, 200, 1280, 1024))),
       ALLOW_THIS_IN_INITIALIZER_LIST(schedule_paint_factory_(this)),
       active_window_(NULL),
       in_destructor_(false) {
-  if (compositor_factory_) {
-    compositor_ = (*Desktop::compositor_factory())();
+  if (ui::Compositor::compositor_factory()) {
+    compositor_ = (*ui::Compositor::compositor_factory())(this);
   } else {
     compositor_ = ui::Compositor::Create(this, host_->GetAcceleratedWidget(),
                                          host_->GetSize());
   }
   gfx::Screen::SetInstance(new internal::ScreenAura);
   host_->SetDesktop(this);
   DCHECK(compositor_.get());
   window_.reset(new internal::RootWindow);
   last_mouse_location_ = host_->QueryMouseLocation();
 }
@@ skipping 137 matching lines @@
 // static
 Desktop* Desktop::GetInstance() {
   if (!instance_) {
     instance_ = new Desktop;
     instance_->Init();
   }
   return instance_;
 }
 
 }  // namespace aura