Plumb overlay processing into DirectRenderer.

gpu/command_buffer/client/context_support.h

Index: gpu/command_buffer/client/context_support.h
diff --git a/gpu/command_buffer/client/context_support.h b/gpu/command_buffer/client/context_support.h
index b5e771368c06de4f13bdb728f5bbbec2b3e79fe8..176fb24c4090aaa948b691acb7bf32f4e86bf6d9 100644
--- a/gpu/command_buffer/client/context_support.h
+++ b/gpu/command_buffer/client/context_support.h
@@ -6,6 +6,7 @@
 #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 {
@@ -33,6 +34,15 @@ class ContextSupport {
   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() {}