Revert of Use transfer buffer for BatchAtlas texture copies

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 375 matching lines @@
         }
     }
 
     if (kGL_GrGLStandard == standard) {
         if (version >= GR_GL_VER(3, 0) || ctxInfo.hasExtension("GL_ARB_pixel_buffer_object")) {
             fTransferBufferType = kPBO_TransferBufferType;
         }
     } else {
         if (version >= GR_GL_VER(3, 0) || ctxInfo.hasExtension("GL_NV_pixel_buffer_object")) {
             fTransferBufferType = kPBO_TransferBufferType;
-// TODO: get transfer buffers working in Chrome
-//        } else if (ctxInfo.hasExtension("GL_CHROMIUM_pixel_transfer_buffer_object")) {
-//            fTransferBufferType = kChromium_TransferBufferType;
+        } else if (ctxInfo.hasExtension("GL_CHROMIUM_pixel_transfer_buffer_object")) {
+            fTransferBufferType = kChromium_TransferBufferType;
         }
     }
 
     // On many GPUs, map memory is very expensive, so we effectively disable it here by setting the
     // threshold to the maximum unless the client gives us a hint that map memory is cheap.
     if (fBufferMapThreshold < 0) {
         // We think mapping on Chromium will be cheaper once we know ahead of time how much space
         // we will use for all GrBatchs. Right now we might wind up mapping a large buffer and using
         // a small subset.
 #if 0
@@ skipping 1494 matching lines @@
         for (int j = 0; j < kExternalFormatUsageCnt; ++j) {
             SkASSERT(defaultEntry.fFormats.fExternalFormat[j] !=
                      fConfigTable[i].fFormats.fExternalFormat[j]);
         }
         SkASSERT(defaultEntry.fFormats.fExternalType != fConfigTable[i].fFormats.fExternalType);
     }
 #endif
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {}