Revert of Revert of Implement software fallback for PPB_VideoDecoder.

gpu/command_buffer/common/cmd_buffer_common.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.
 
 // This file contains the binary format definition of the command buffer and
 // command buffer commands.
 
 #include "gpu/command_buffer/common/cmd_buffer_common.h"
 
 #include "gpu/command_buffer/common/command_buffer.h"
@@ skipping 13 matching lines @@
 
   #undef COMMON_COMMAND_BUFFER_CMD_OP
   };
 
   int id = static_cast<int>(command_id);
   return (id >= 0 && id < kNumCommands) ? names[id] : "*unknown-command*";
 }
 
 }  // namespace cmd
 
+#if !defined(NACL_WIN64)
 // TODO(apatrick): this is a temporary optimization while skia is calling
 // RendererGLContext::MakeCurrent prior to every GL call. It saves returning 6
 // ints redundantly when only the error is needed for the CommandBufferProxy
 // implementation.
 error::Error CommandBuffer::GetLastError() {
   return GetLastState().error;
 }
+#endif
 
 }  // namespace gpu