Plumb overlay processing into DirectRenderer.

gpu/command_buffer/client/context_support.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 GPU_COMMAND_BUFFER_CLIENT_CONTEXT_SUPPORT_H_
 #define GPU_COMMAND_BUFFER_CLIENT_CONTEXT_SUPPORT_H_
 
 #include "base/callback.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "ui/gfx/rect.h"
 
 namespace gpu {
 struct ManagedMemoryStats;
 
 class ContextSupport {
  public:
   // Runs |callback| when a sync point is reached.
   virtual void SignalSyncPoint(uint32 sync_point,
                                const base::Closure& callback) = 0;
 
   // Runs |callback| when a query created via glCreateQueryEXT() has cleared
   // passed the glEndQueryEXT() point.
   virtual void SignalQuery(uint32 query, const base::Closure& callback) = 0;
 
   // For onscreen contexts, indicates that the surface visibility has changed.
   // Clients aren't expected to draw to an invisible surface.
   virtual void SetSurfaceVisible(bool visible) = 0;
 
   virtual void SendManagedMemoryStats(const ManagedMemoryStats& stats) = 0;
 
   virtual void Swap() = 0;
   virtual void PartialSwapBuffers(const gfx::Rect& sub_buffer) = 0;
 
   virtual void SetSwapBuffersCompleteCallback(
       const base::Closure& callback) = 0;
 
+  // Schedule a texture to be presented as an overlay synchronously with the
+  // primary surface during the next buffer swap.
+  // This method is not stateful and needs to be re-scheduled every frame.
+  virtual void ScheduleOverlayPlane(int plane_z_order,
+                                    unsigned plane_transform,

[alexst (slow to review), 2014/03/26 20:48:50]

Is //src/gpu/command_buffer/common/constants.h a reasonable place to move the
enum into for sharing it here?

+                                    const gpu::Mailbox& overlay_texture,
+                                    const gfx::Rect& display_bounds,
+                                    const gfx::RectF& uv_rect) = 0;
+
  protected:
   ContextSupport() {}
   virtual ~ContextSupport() {}
 };
 
 }
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_CONTEXT_SUPPORT_H_