Add R_8 GPU memory buffers format.

gpu/command_buffer/client/gles2_implementation.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2ext.h>
 #include <GLES2/gl2extchromium.h>
@@ skipping 4811 matching lines @@
                      << sync_point << ")");
   DCHECK(capabilities_.future_sync_points);
   helper_->CommandBufferHelper::Flush();
   gpu_control_->RetireSyncPoint(sync_point);
 }
 
 namespace {
 
 bool ValidImageFormat(GLenum internalformat) {
   switch (internalformat) {
+    case GL_R8:
     case GL_RGB:
     case GL_RGBA:
     case GL_BGRA_EXT:
       return true;
     default:
       return false;
   }
 }
 
 bool ValidImageUsage(GLenum usage) {
@@ skipping 286 matching lines @@
   CheckGLError();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu