More framework support for TransferBuffers

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index d1b0802721e97e8005f3491238da1c295eeb429e..f07bf03b13ebb3a1aad5b8f68cffa6a79aea525e 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -266,6 +266,25 @@ public:
                      size_t rowBytes);
 
     /**
+    * Updates the pixels in a rectangle of a surface using a GrTransferBuffer
+    *
+    * @param surface       The surface to write to.
+    * @param left          left edge of the rectangle to write (inclusive)
+    * @param top           top edge of the rectangle to write (inclusive)
+    * @param width         width of rectangle to write in pixels.
+    * @param height        height of rectangle to write in pixels.
+    * @param config        the pixel config of the source buffer
+    * @param buffer        GrTransferBuffer to read pixels from
+    * @param offset        offset from the start of the buffer
+    * @param rowBytes      number of bytes between consecutive rows. Zero
+    *                      means rows are tightly packed.
+    */
+    bool transferPixels(GrSurface* surface,
+                        int left, int top, int width, int height,
+                        GrPixelConfig config, GrTransferBuffer* buffer,
+                        size_t offset, size_t rowBytes);
+
+    /**
      * Clear the passed in render target. Ignores the draw state and clip.
      */
     void clear(const SkIRect& rect, GrColor color, GrRenderTarget* renderTarget);
@@ -508,6 +527,12 @@ private:
                                GrPixelConfig config, const void* buffer,
                                size_t rowBytes) = 0;
 
+    // overridden by backend-specific derived class to perform the surface write
+    virtual bool onTransferPixels(GrSurface*,
+                                  int left, int top, int width, int height,
+                                  GrPixelConfig config, GrTransferBuffer* buffer,
+                                  size_t offset, size_t rowBytes) = 0;
+
     // overridden by backend-specific derived class to perform the resolve
     virtual void onResolveRenderTarget(GrRenderTarget* target) = 0;