WIP: move OffscreenCanvas into new display compositor

components/display_compositor/gpu_compositor_frame_sink_base.h

Index: components/display_compositor/gpu_compositor_frame_sink_base.h
diff --git a/components/display_compositor/gpu_compositor_frame_sink_base.h b/components/display_compositor/gpu_compositor_frame_sink_base.h
new file mode 100644
index 0000000000000000000000000000000000000000..aa6b382c63b6eb84485445965fd64fd031cf2ce8
--- /dev/null
+++ b/components/display_compositor/gpu_compositor_frame_sink_base.h
@@ -0,0 +1,48 @@
+// Copyright 2017 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_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_BASE_H_
+#define COMPONENTS_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_BASE_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "components/display_compositor/gpu_compositor_frame_sink.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace display_compositor {
+
+// Server side representation of a WindowSurface.
+class DISPLAY_COMPOSITOR_EXPORT GpuCompositorFrameSinkBase
+    : public GpuCompositorFrameSink,
+      public NON_EXPORTED_BASE(cc::mojom::MojoCompositorFrameSinkPrivate) {
+ public:
+  GpuCompositorFrameSinkBase(
+      GpuCompositorFrameSinkDelegate* delegate,
+      std::unique_ptr<cc::CompositorFrameSinkSupport>,
+      cc::mojom::MojoCompositorFrameSinkPrivateRequest private_request,
+      cc::mojom::MojoCompositorFrameSinkClientPtr client);
+
+  ~GpuCompositorFrameSinkBase() override;
+
+  // cc::mojom::MojoCompositorFrameSinkPrivate:
+  void AddChildFrameSink(const cc::FrameSinkId& child_frame_sink_id) override;
+  void RemoveChildFrameSink(
+      const cc::FrameSinkId& child_frame_sink_id) override;
+
+ protected:
+  void OnPrivateConnectionLost();
+
+ private:
+  mojo::Binding<cc::mojom::MojoCompositorFrameSinkPrivate>
+      compositor_frame_sink_private_binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuCompositorFrameSinkBase);
+};
+
+}  // namespace display_compositor
+
+#endif  // COMPONENTS_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_BASE_H_