Use transfer buffer for BatchAtlas texture copies

src/gpu/GrBatchFlushState.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrBatchBuffer_DEFINED
 #define GrBatchBuffer_DEFINED
 
@@ skipping 59 matching lines @@
     }
 
     void doUpload(GrDrawBatch::DeferredUploadFn& upload) {
         GrDrawBatch::WritePixelsFn wp = [this] (GrSurface* surface,
                 int left, int top, int width, int height,
                 GrPixelConfig config, const void* buffer,
                 size_t rowBytes) -> bool {
             return this->fGpu->writePixels(surface, left, top, width, height, config, buffer,
                                            rowBytes);
         };
-        upload(wp);
+        GrDrawBatch::TransferPixelsFn tp = [this](GrSurface* surface,
+                                                int left, int top, int width, int height,
+                                                GrPixelConfig config, GrBuffer* buffer,
+                                                size_t offset, size_t rowBytes) -> bool {
+            return this->fGpu->transferPixels(surface, left, top, width, height, config, buffer, 
+                                              offset, rowBytes);
+        };
+        upload(wp, tp);
     }
 
     void putBackIndices(size_t indices) { fIndexPool.putBack(indices * sizeof(uint16_t)); }
 
     void putBackVertexSpace(size_t sizeInBytes) { fVertexPool.putBack(sizeInBytes); }
 
     GrGpu* gpu() { return fGpu; }
 
     void reset() {
         fVertexPool.reset();
@@ skipping 104 matching lines @@
     void putBackVertices(int vertices, size_t vertexStride) {
         this->state()->putBackVertexSpace(vertices * vertexStride);
     }
 
 private:
     GrVertexBatch* vertexBatch() { return static_cast<GrVertexBatch*>(this->batch()); }
     typedef GrDrawBatch::Target INHERITED;
 };
 
 #endif