Fix crash when backgrounding MojoShell on Android. Fixes issue #186.

services/gles2/command_buffer_impl.h

 // Copyright 2014 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 SERVICES_GLES2_COMMAND_BUFFER_IMPL_H_
 #define SERVICES_GLES2_COMMAND_BUFFER_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
-#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/services/gpu/public/interfaces/command_buffer.mojom.h"
 #include "mojo/services/gpu/public/interfaces/viewport_parameter_listener.mojom.h"
 
 namespace gpu {
 class SyncPointManager;
 }
 
 namespace gles2 {
 class CommandBufferDriver;
 
 // This class listens to the CommandBuffer message pipe on a low-latency thread
 // so that we can insert sync points without blocking on the GL driver. It
 // forwards most method calls to the CommandBufferDriver, which runs on the
 // same thread as the native viewport.
-class CommandBufferImpl : public mojo::CommandBuffer {
+class CommandBufferImpl : public mojo::CommandBuffer, mojo::ErrorHandler {
  public:
   class Observer {
    public:
     virtual void OnCommandBufferImplDestroyed() = 0;
   };
 
   CommandBufferImpl(
       mojo::InterfaceRequest<CommandBuffer> request,
       mojo::ViewportParameterListenerPtr listener,
       scoped_refptr<base::SingleThreadTaskRunner> control_task_runner,
@@ skipping 13 matching lines @@
                               uint32_t size) override;
   void DestroyTransferBuffer(int32_t id) override;
   void InsertSyncPoint(bool retire) override;
   void RetireSyncPoint(uint32_t sync_point) override;
   void Echo(const mojo::Callback<void()>& callback) override;
 
   void DidLoseContext();
   void UpdateVSyncParameters(base::TimeTicks timebase,
                              base::TimeDelta interval);
 
+  // Sets an observer for CommandBufferImpl destruction. An observer registered
+  // here will be notified of the destruction of this object on the thread used
+  // to create it, before the destruction happens.
   void set_observer(Observer* observer) { observer_ = observer; }
 
+  // mojo::ErrorHandler implementation
+  void OnConnectionError() override;
+
  private:
   void BindToRequest(mojo::InterfaceRequest<CommandBuffer> request);
+  void NotifyAndDestroy();
+  void Destroy();
 
   scoped_refptr<gpu::SyncPointManager> sync_point_manager_;
+  scoped_refptr<base::SingleThreadTaskRunner> control_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> driver_task_runner_;
   scoped_ptr<CommandBufferDriver> driver_;
   mojo::CommandBufferSyncPointClientPtr sync_point_client_;
   mojo::ViewportParameterListenerPtr viewport_parameter_listener_;
-  mojo::StrongBinding<CommandBuffer> binding_;
+  mojo::Binding<CommandBuffer> binding_;
   Observer* observer_;
 
   base::WeakPtrFactory<CommandBufferImpl> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(CommandBufferImpl);
 };
 
 }  // namespace gles2
 
 #endif  // SERVICES_GLES2_COMMAND_BUFFER_IMPL_H_