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 <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 26 matching lines @@
 static const int kDefaultHostWindowX = 200;
 static const int kDefaultHostWindowY = 200;
 static const int kDefaultHostWindowWidth = 1280;
 static const int kDefaultHostWindowHeight = 1024;
 
 }  // namespace
 
 // static
 Desktop* Desktop::instance_ = NULL;
 
-// static
-ui::Compositor*(*Desktop::compositor_factory_)() = NULL;
-
 Desktop::Desktop()
     : Window(NULL),
       host_(aura::DesktopHost::Create(GetInitialHostWindowBounds())),
       ALLOW_THIS_IN_INITIALIZER_LIST(schedule_paint_factory_(this)),
       active_window_(NULL),
       in_destructor_(false),
       screen_(new ScreenAura),
       capture_window_(NULL),
       mouse_pressed_handler_(NULL),
       mouse_moved_handler_(NULL),
       focused_window_(NULL),
       touch_event_handler_(NULL) {
   set_name("RootWindow");
   gfx::Screen::SetInstance(screen_);
   host_->SetDesktop(this);
   last_mouse_location_ = host_->QueryMouseLocation();
 
-  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());
   }
   DCHECK(compositor_.get());
 }
 
 Desktop::~Desktop() {
   in_destructor_ = true;
   if (instance_ == this)
@@ skipping 348 matching lines @@
       !base::StringToInt(parts[0], &width) ||
       !base::StringToInt(parts[1], &height) ||
       width <= 0 || height <= 0) {
     width = kDefaultHostWindowWidth;
     height = kDefaultHostWindowHeight;
   }
   return gfx::Rect(kDefaultHostWindowX, kDefaultHostWindowY, width, height);
 }
 
 }  // namespace aura