Android: Explicitly tear down LayerTreeHost first, take 2

content/browser/renderer_host/compositor_impl_android.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_
 #define CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_
 
 #include <stddef.h>
 
 #include "base/cancelable_callback.h"
@@ skipping 144 matching lines @@
   void CreateLayerTreeHost();
 
   void OnGpuChannelEstablished();
   void OnGpuChannelTimeout();
 
   // root_layer_ is the persistent internal root layer, while subroot_layer_
   // is the one attached by the compositor client.
   scoped_refptr<cc::Layer> root_layer_;
   scoped_refptr<cc::Layer> subroot_layer_;
 
+  // Destruction order matters here:
+  base::ObserverList<VSyncObserver, true> observer_list_;
   scoped_ptr<cc::LayerTreeHost> host_;
   ui::ResourceManagerImpl resource_manager_;
 
   scoped_ptr<cc::OnscreenDisplayClient> display_client_;
   scoped_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
 
   gfx::Size size_;
   bool has_transparent_background_;
   float device_scale_factor_;
 
@@ skipping 40 matching lines @@
   base::OneShotTimer establish_gpu_channel_timeout_;
 
   // Whether there is an OutputSurface request pending from the current
   // |host_|. Becomes |true| if RequestNewOutputSurface is called, and |false|
   // if |host_| is deleted or we succeed in creating *and* initializing an
   // OutputSurface (which is essentially the contract with cc).
   bool output_surface_request_pending_;
 
   gpu::Capabilities gpu_capabilities_;
 
-  base::ObserverList<VSyncObserver, true> observer_list_;
-
   base::WeakPtrFactory<CompositorImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorImpl);
 };
 
 } // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_