[cc] Mailbox Output Surface Support

content/renderer/gpu/mailbox_output_surface.h

+// Copyright (c) 2012 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 CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_
+#define CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_
+
+#include <queue>
+
+#include "cc/transferable_resource.h"
+#include "content/renderer/gpu/compositor_output_surface.h"
+#include "ui/gfx/size.h"
+
+namespace cc {
+class CompositorFrameAck;
+}
+
+namespace content {
+
+// Implementation of CompositorOutputSurface that renders to textures which
+// are sent to the browser through the mailbox extension.
+// This class can be created only on the main thread, but then becomes pinned
+// to a fixed thread when bindToClient is called.
+class MailboxOutputSurface : public CompositorOutputSurface {
+ public:
+  MailboxOutputSurface(int32 routing_id,
+                       WebKit::WebGraphicsContext3D* context3d,
+                       cc::SoftwareOutputDevice* software);
+  virtual ~MailboxOutputSurface();
+
+  // cc::OutputSurface implementation.
+  virtual void SendFrameToParentCompositor(cc::CompositorFrame* frame) OVERRIDE;
+  virtual void EnsureBackbuffer() OVERRIDE;
+  virtual void DiscardBackbuffer() OVERRIDE;
+  virtual void Reshape(const gfx::Size& size) OVERRIDE;
+  virtual void BindFramebuffer() OVERRIDE;
+  virtual void PostSubBuffer(const gfx::Rect& rect) OVERRIDE;
+  virtual void SwapBuffers() OVERRIDE;
+
+ private:
+  // CompositorOutputSurface overrides.
+  virtual void OnSwapAck(const cc::CompositorFrameAck& ack) OVERRIDE;
+
+  struct TransferableFrame
+  {
+    TransferableFrame()
+        : texture_id(0) {}
+
+    TransferableFrame(uint32 texture_id,
+                      const cc::Mailbox& mailbox,
+                      const gfx::Size& size)

[Sami, 2013/02/28 12:46:58]

Nit: pass by value.

[no sievers, 2013/02/28 18:43:40]

Done.

+        : texture_id(texture_id),
+          mailbox(mailbox),
+          size(size) {}
+
+    uint32 texture_id;
+    cc::Mailbox mailbox;
+    gfx::Size size;
+  };
+  TransferableFrame current_backing_;
+  std::queue<TransferableFrame> returned_textures_;
+
+  gfx::Size size_;
+  uint32 fbo_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_