Introduce command buffer control thread

mojo/services/gles2/command_buffer_impl.h

Index: mojo/services/gles2/command_buffer_impl.h
diff --git a/mojo/services/gles2/command_buffer_impl.h b/mojo/services/gles2/command_buffer_impl.h
index 44ff14ca5cc7d50eebf1bd34b44234dad8fe21f6..a28112e454e1262cb0bc54d82abf7dc20af99980 100644
--- a/mojo/services/gles2/command_buffer_impl.h
+++ b/mojo/services/gles2/command_buffer_impl.h
@@ -6,6 +6,8 @@
 #define MOJO_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/services/public/interfaces/gpu/command_buffer.mojom.h"
 
@@ -14,27 +16,33 @@ class CommandBufferDriver;
 
 class CommandBufferImpl : public CommandBuffer {

[jamesr, 2014/11/19 06:43:02]

could use a class level comment

[abarth-chromium, 2014/11/19 16:54:10]

Done.

  public:
-  CommandBufferImpl(InterfaceRequest<CommandBuffer> request,
-                    scoped_ptr<CommandBufferDriver> driver);
+  CommandBufferImpl(
+      InterfaceRequest<CommandBuffer> request,
+      scoped_refptr<base::SingleThreadTaskRunner> control_task_runner,
+      scoped_ptr<CommandBufferDriver> driver);
   ~CommandBufferImpl() override;
 
   void Initialize(CommandBufferSyncClientPtr sync_client,
-                  mojo::ScopedSharedBufferHandle shared_state) override;
+                  ScopedSharedBufferHandle shared_state) override;
   void SetGetBuffer(int32_t buffer) override;
   void Flush(int32_t put_offset) override;
   void MakeProgress(int32_t last_get_offset) override;
   void RegisterTransferBuffer(int32_t id,
-                              mojo::ScopedSharedBufferHandle transfer_buffer,
+                              ScopedSharedBufferHandle transfer_buffer,
                               uint32_t size) override;
   void DestroyTransferBuffer(int32_t id) override;
   void Echo(const Callback<void()>& callback) override;
 
  private:
+  void BindToRequest(InterfaceRequest<CommandBuffer> request);
   void OnContextLost(int32_t reason);
 
-  StrongBinding<CommandBuffer> binding_;
+  scoped_refptr<base::SingleThreadTaskRunner> driver_task_runner_;
   scoped_ptr<CommandBufferDriver> driver_;
 
+  scoped_ptr<StrongBinding<CommandBuffer>> binding_;

[jamesr, 2014/11/19 06:43:02]

hmm, no inherent need to have a scoped_ptr<> to the binding.  with Binding<> you
can allocate a binding and associate it with an interface without binding it to
a pipe+thread, then later call .Bind() to do the actual hookup. I didn't add the
Bind() calls to StrongBinding<> (although the interface-only c'tor is there)
because i couldn't think of a case where it was needed but i clearly wasn't
creative enough.  could you add void Bind(InterfaceRequest<Interface>) to
StrongBinding<> and use that instead of the extra heap allocation here?

[abarth-chromium, 2014/11/19 15:42:11]

Sure thing.

+  base::WeakPtrFactory<CommandBufferImpl> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(CommandBufferImpl);
 };