Add support for using glCopyTexSubImage2D when possible to copy surfaces.

src/gpu/GrDrawTarget.h

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef GrDrawTarget_DEFINED
@@ skipping 414 matching lines @@
     /**
      * Function that determines whether a copySurface call would succeed without
      * performing the copy.
      */
     bool canCopySurface(GrSurface* dst,
                         GrSurface* src,
                         const SkIRect& srcRect,
                         const SkIPoint& dstPoint);
 
     /**
+     * This is can be called before allocating a texture to be a dst for copySurface. It will
+     * populate the origin, config, and flags fields of the desc such that copySurface is more
+     * likely to succeed and be efficient.
+     */
+    virtual void initCopySurfaceDstDesc(const GrSurface* src, GrTextureDesc* desc);
+
+
+    /**
      * Release any resources that are cached but not currently in use. This
      * is intended to give an application some recourse when resources are low.
      */
     virtual void purgeResources() {};
 
     /**
      * For subclass internal use to invoke a call to onDraw(). See DrawInfo below.
      */
     void executeDraw(const DrawInfo& info) { this->onDraw(info); }
 
@@ skipping 375 matching lines @@
     const GrClipData*                                               fClip;
     GrDrawState*                                                    fDrawState;
     GrDrawState                                                     fDefaultDrawState;
     // The context owns us, not vice-versa, so this ptr is not ref'ed by DrawTarget.
     GrContext*                                                      fContext;
 
     typedef GrRefCnt INHERITED;
 };
 
 #endif