Plumb GpuSwapBuffers completion from Mus GPU thread to WS thread

components/mus/gles2/gl_surface_adapter.h

Index: components/mus/gles2/gl_surface_adapter.h
diff --git a/components/mus/gles2/gl_surface_adapter.h b/components/mus/gles2/gl_surface_adapter.h
new file mode 100644
index 0000000000000000000000000000000000000000..df7d10e6509f92c74220d826ec663b157a42225c
--- /dev/null
+++ b/components/mus/gles2/gl_surface_adapter.h
@@ -0,0 +1,71 @@
+// Copyright (c) 2016 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_MUS_GLES2_GL_SURFACE_ADAPTER_H_
+#define COMPONENTS_MUS_GLES2_GL_SURFACE_ADAPTER_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "ui/gfx/swap_result.h"
+#include "ui/gl/gl_surface.h"
+
+namespace mus {
+
+// Wraps a GLSurface such that there is a real GLSurface instance acting as
+// delegate. Implements the GLSurface interface. The |gfx::GLSurfaceAdapter|
+// superclass provides a default implementation that forwards all GLSurface
+// methods to the provided delegate. |GLSurfaceAdapterMus| overrides only the
+// necessary methods to augment the completion callback argument to
+// |SwapBuffersAsync|, |PostSubBufferAsync| and |CommitOverlayPlanesAsync| with
+// a callback provided with the |SetGpuCompletedSwapBuffersCallback| method.
+class GLSurfaceAdapterMus : public gfx::GLSurfaceAdapter {
+ public:
+  // Creates a new |GLSurfaceAdapterMus| that delegates to |surface|.
+  explicit GLSurfaceAdapterMus(scoped_refptr<gfx::GLSurface> surface);
+
+  // gfx::GLSurfaceAdapter.
+  void SwapBuffersAsync(
+      const gfx::GLSurface::SwapCompletionCallback& callback) override;
+  void PostSubBufferAsync(
+      int x,
+      int y,
+      int width,
+      int height,
+      const gfx::GLSurface::SwapCompletionCallback& callback) override;
+  void CommitOverlayPlanesAsync(
+      const gfx::GLSurface::SwapCompletionCallback& callback) override;
+
+  // Set an additional callback to run on SwapBuffers completion.
+  void SetGpuCompletedSwapBuffersCallback(
+      gfx::GLSurface::SwapCompletionCallback callback);
+
+ private:
+  ~GLSurfaceAdapterMus() override;
+
+  // We wrap the callback given to the |gfx::GLSurfaceAdapter| overrides above
+  // with an invocation of this function. It invokes |adapter_callback_| and the
+  // original |original_callback| provided by the original invoker of
+  // |SwapBuffersAsync| etc.
+  void WrappedCallbackForSwapBuffersAsync(
+      const gfx::GLSurface::SwapCompletionCallback& original_callback,
+      gfx::SwapResult result);
+
+  gfx::GLSurface::SwapCompletionCallback adapter_callback_;
+
+  // gfx::GLSurfaceAdapter doesn't own the delegate surface so keep a reference
+  // here.
+  scoped_refptr<gfx::GLSurface> surface_;
+
+  base::WeakPtrFactory<GLSurfaceAdapterMus> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GLSurfaceAdapterMus);
+};
+
+}  // namespace mus
+
+#endif  // COMPONENTS_MUS_GLES2_GL_SURFACE_ADAPTER_H_