[Chromecast] Include output screen resolution in OSD rect info

chromecast/public/osd_plane.h

 // Copyright (c) 2015 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 CHROMECAST_PUBLIC_OSD_PLANE_H_
 #define CHROMECAST_PUBLIC_OSD_PLANE_H_
 
 namespace chromecast {
 
 class OsdSurface;
 struct Rect;
 struct Size;
 
 // Abstract graphics plane for OSD, to be implemented in platform-specific way.
 // Platform must composite this plane on top of main (GL-based) graphics plane.
 class OsdPlane {
  public:
   virtual ~OsdPlane() {}
 
   // Creates a surface for offscreen drawing.
   virtual OsdSurface* CreateSurface(const Size& size) = 0;
 
   // Sets a clip rectangle, client should call before drawing to back buffer
   // to specify the area they intend to draw on.  Platforms may reduce memory
   // usage by only allocating back buffer to cover this area.  Areas outside
   // clip rectangle must display as fully transparent.  In particular, setting
   // an empty clip rectangle and calling Flip should clear the plane.
-  virtual void SetClipRectangle(const Rect& rect) = 0;
+  // |osd_res| gives the resolution of the full OSD plane, i.e. |rect| is
+  // a subrectangle of this area.  |output_scale| specifies the current scaling
+  // from |osd_res| to output screen resolution.
+  virtual void SetClipRectangle(const Rect& rect,
+                                const Size& osd_res,
+                                float output_scale) = 0;
 
   // Gets the current back buffer surface.  Valid until next call to Flip or
   // SetClipRectangle.
   virtual OsdSurface* GetBackBuffer() = 0;
 
   // Presents current back buffer to screen.
   virtual void Flip() = 0;
 };
 
 }  // namespace chromecast
 
 #endif  // CHROMECAST_PUBLIC_OSD_PLANE_H