Use transfer buffer for BatchAtlas texture copies

src/gpu/gl/GrGLBuffer.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLBuffer.h"
 #include "GrGLGpu.h"
 #include "SkTraceMemoryDump.h"
@@ skipping 12 matching lines @@
 #endif
 
 #ifdef SK_DEBUG
 #define VALIDATE() this->validate()
 #else
 #define VALIDATE() do {} while(false)
 #endif
 
 GrGLBuffer* GrGLBuffer::Create(GrGLGpu* gpu, size_t size, GrBufferType intendedType,
                                GrAccessPattern accessPattern, const void* data) {
+    if (gpu->glCaps().transferBufferType() == GrGLCaps::kNone_TransferBufferType &&
+        (kXferCpuToGpu_GrBufferType == intendedType ||
+        kXferGpuToCpu_GrBufferType == intendedType)) {
+        return nullptr;
+    }
+
     SkAutoTUnref<GrGLBuffer> buffer(new GrGLBuffer(gpu, size, intendedType, accessPattern, data));
     if (0 == buffer->bufferID()) {
         return nullptr;
     }
     return buffer.release();
 }
 
 // GL_STREAM_DRAW triggers an optimization in Chromium's GPU process where a client's vertex buffer
 // objects are implemented as client-side-arrays on tile-deferred architectures.
 #define DYNAMIC_DRAW_PARAM GR_GL_STREAM_DRAW
@@ skipping 236 matching lines @@
 }
 
 #ifdef SK_DEBUG
 
 void GrGLBuffer::validate() const {
     SkASSERT(0 != fBufferID || 0 == fGLSizeInBytes);
     SkASSERT(nullptr == fMapPtr || fGLSizeInBytes <= this->sizeInBytes());
 }
 
 #endif