Make Mandoline shut down cleanly.

components/gles2/command_buffer_driver.h

 // Copyright 2013 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 COMPONENTS_GLES2_COMMAND_BUFFER_DRIVER_H_
 #define COMPONENTS_GLES2_COMMAND_BUFFER_DRIVER_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/timer/timer.h"
 #include "components/gpu/public/interfaces/command_buffer.mojom.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gpu {
 class CommandBufferService;
 class GpuScheduler;
 class GpuControlService;
 class SyncPointManager;
 namespace gles2 {
 class GLES2Decoder;
 class MailboxManager;
 }
 }
 
 namespace gfx {
 class GLContext;
 class GLShareGroup;
 class GLSurface;
 }
 
 namespace gles2 {
 
+// This class receives CommandBuffer messages on the same thread as the native
+// viewport. It is usually destructed on that thread, however if the native
+// viewport app is destroyed before CommandBufferImpl, then the latter's failed
+// PostTask will end up deleting this class on the control thread.
 class CommandBufferDriver {
  public:
   class Client {
    public:
     virtual ~Client();
     virtual void UpdateVSyncParameters(base::TimeTicks timebase,
                                        base::TimeDelta interval) = 0;
     virtual void DidLoseContext() = 0;
   };
   // Offscreen.
   CommandBufferDriver(gfx::GLShareGroup* share_group,
                       gpu::gles2::MailboxManager* mailbox_manager,
                       gpu::SyncPointManager* sync_point_manager);
   // Onscreen.
-  CommandBufferDriver(gfx::AcceleratedWidget widget,
-                      gfx::GLShareGroup* share_group,
-                      gpu::gles2::MailboxManager* mailbox_manager,
-                      gpu::SyncPointManager* sync_point_manager);
+  CommandBufferDriver(
+      gfx::AcceleratedWidget widget,
+      gfx::GLShareGroup* share_group,
+      gpu::gles2::MailboxManager* mailbox_manager,
+      gpu::SyncPointManager* sync_point_manager,
+      const base::Callback<void(CommandBufferDriver*)>& destruct_callback);
   ~CommandBufferDriver();
 
   void set_client(scoped_ptr<Client> client) { client_ = client.Pass(); }
 
   void Initialize(mojo::CommandBufferSyncClientPtr sync_client,
                   mojo::CommandBufferLostContextObserverPtr loss_observer,
                   mojo::ScopedSharedBufferHandle shared_state);
   void SetGetBuffer(int32_t buffer);
   void Flush(int32_t put_offset);
   void MakeProgress(int32_t last_get_offset);
   void RegisterTransferBuffer(int32_t id,
                               mojo::ScopedSharedBufferHandle transfer_buffer,
                               uint32_t size);
   void DestroyTransferBuffer(int32_t id);
   void Echo(const mojo::Callback<void()>& callback);
 
+  // Called at shutdown to destroy the X window. This is needed when the parent
+  // window is being destroyed. Otherwise X calls for this window will fail.
+  void DestroyWindow();
+
  private:
   bool DoInitialize(mojo::ScopedSharedBufferHandle shared_state);
   void OnResize(gfx::Size size, float scale_factor);
   bool OnWaitSyncPoint(uint32_t sync_point);
   void OnSyncPointRetired();
   void OnParseError();
   void OnContextLost(uint32_t reason);
   void OnUpdateVSyncParameters(const base::TimeTicks timebase,
                                const base::TimeDelta interval);
+  void DestroyDecoder();
 
   scoped_ptr<Client> client_;
   mojo::CommandBufferSyncClientPtr sync_client_;
   mojo::CommandBufferLostContextObserverPtr loss_observer_;
   gfx::AcceleratedWidget widget_;
   scoped_ptr<gpu::CommandBufferService> command_buffer_;
   scoped_ptr<gpu::gles2::GLES2Decoder> decoder_;
   scoped_ptr<gpu::GpuScheduler> scheduler_;
   scoped_refptr<gfx::GLContext> context_;
   scoped_refptr<gfx::GLSurface> surface_;
   scoped_refptr<gfx::GLShareGroup> share_group_;
   scoped_refptr<gpu::gles2::MailboxManager> mailbox_manager_;
   scoped_refptr<gpu::SyncPointManager> sync_point_manager_;
 
   scoped_refptr<base::SingleThreadTaskRunner> context_lost_task_runner_;
   base::Callback<void(int32_t)> context_lost_callback_;
 
+  base::Callback<void(CommandBufferDriver*)> destruct_callback_;
+
   base::WeakPtrFactory<CommandBufferDriver> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CommandBufferDriver);
 };
 
 }  // namespace gles2
 
 #endif  // COMPONENTS_GLES2_COMMAND_BUFFER_DRIVER_H_