Add support for using glCopyTexSubImage2D when possible to copy surfaces.

src/gpu/gl/GrGpuGL.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #ifndef GrGpuGL_DEFINED
@@ skipping 37 matching lines @@
     virtual GrPixelConfig preferredWritePixelsConfig(GrPixelConfig config) const SK_OVERRIDE;
     virtual bool canWriteTexturePixels(const GrTexture*, GrPixelConfig srcConfig) const SK_OVERRIDE;
     virtual bool readPixelsWillPayForYFlip(
                                     GrRenderTarget* renderTarget,
                                     int left, int top,
                                     int width, int height,
                                     GrPixelConfig config,
                                     size_t rowBytes) const SK_OVERRIDE;
     virtual bool fullReadPixelsIsFasterThanPartial() const SK_OVERRIDE;
 
+    virtual void initCopySurfaceDstDesc(const GrSurface* src, GrTextureDesc* desc) SK_OVERRIDE;
+
     virtual void abandonResources() SK_OVERRIDE;
 
     const GrGLCaps& glCaps() const { return *fGLContext.info().caps(); }
 
     // These functions should be used to bind GL objects. They track the GL state and skip redundant
     // bindings. Making the equivalent glBind calls directly will confuse the state tracking.
     void bindVertexArray(GrGLuint id) {
         fHWGeometryState.setVertexArrayID(this, id);
     }
     void bindIndexBufferAndDefaultVertexArray(GrGLuint id) {
@@ skipping 21 matching lines @@
     virtual bool onCopySurface(GrSurface* dst,
                                GrSurface* src,
                                const SkIRect& srcRect,
                                const SkIPoint& dstPoint) SK_OVERRIDE;
 
     virtual bool onCanCopySurface(GrSurface* dst,
                                   GrSurface* src,
                                   const SkIRect& srcRect,
                                   const SkIPoint& dstPoint) SK_OVERRIDE;
 
-
 private:
     // GrGpu overrides
     virtual void onResetContext() SK_OVERRIDE;
 
     virtual GrTexture* onCreateTexture(const GrTextureDesc& desc,
                                        const void* srcData,
                                        size_t rowBytes) SK_OVERRIDE;
     virtual GrVertexBuffer* onCreateVertexBuffer(uint32_t size,
                                                  bool dynamic) SK_OVERRIDE;
     virtual GrIndexBuffer* onCreateIndexBuffer(uint32_t size,
@@ skipping 327 matching lines @@
     ///@}
 
     // we record what stencil format worked last time to hopefully exit early
     // from our loop that tries stencil formats and calls check fb status.
     int fLastSuccessfulStencilFmtIdx;
 
     typedef GrGpu INHERITED;
 };
 
 #endif