Fix assert with webkit compositor. The assert was hitting because we

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 411 matching lines @@
     ui::CompositorCC::Initialize(false);
 #endif
     compositor_ = ui::Compositor::Create(this, host_->GetAcceleratedWidget(),
                                          host_->GetSize());
   }
   DCHECK(compositor_.get());
 }
 
 Desktop::~Desktop() {
   in_destructor_ = true;
+  // Make sure to destroy the compositor before terminating so that state is
+  // cleared and we don't hit asserts.
+  compositor_ = NULL;
 #ifdef USE_WEBKIT_COMPOSITOR
   if (!ui::Compositor::compositor_factory())
     ui::CompositorCC::Terminate();
 #endif
   if (instance_ == this)
     instance_ = NULL;
 }
 
 void Desktop::HandleMouseMoved(const MouseEvent& event, Window* target) {
   if (target == mouse_moved_handler_)
@@ skipping 157 matching lines @@
       base::StringToInt(parts[1], &parsed_height) && parsed_height > 0) {
     bounds.set_size(gfx::Size(parsed_width, parsed_height));
   } else if (use_fullscreen_host_window_) {
     bounds = gfx::Rect(DesktopHost::GetNativeScreenSize());
   }
 
   return bounds;
 }
 
 }  // namespace aura