Add support for GL_CHROMIUM_pixel_transfer_buffer_object.

gpu/gpu_common.gypi

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
     # These are defined here because we need to build this library twice. Once
     # with extra parameter checking. Once with no parameter checking to be 100%
     # OpenGL ES 2.0 compliant for the conformance tests.
     'gles2_c_lib_source_files': [
       'command_buffer/client/gles2_c_lib.cc',
       'command_buffer/client/gles2_c_lib_autogen.h',
       'command_buffer/client/gles2_c_lib_export.h',
       'command_buffer/client/gles2_lib.h',
       'command_buffer/client/gles2_lib.cc',
     ],
     # These are defined here because we need to build this library twice. Once
     # with without support for client side arrays and once with for pepper and
     # the OpenGL ES 2.0 compliant for the conformance tests.
     'gles2_implementation_source_files': [
+      'command_buffer/client/buffer_tracker.cc',
+      'command_buffer/client/buffer_tracker.h',
       'command_buffer/client/gles2_impl_export.h',
       'command_buffer/client/gles2_implementation_autogen.h',
       'command_buffer/client/gles2_implementation.cc',
       'command_buffer/client/gles2_implementation.h',
       'command_buffer/client/gles2_implementation_impl_autogen.h',
       'command_buffer/client/gles2_interface.h',
       'command_buffer/client/gles2_interface.cc',
       'command_buffer/client/program_info_manager.cc',
       'command_buffer/client/program_info_manager.h',
       'command_buffer/client/query_tracker.cc',
@@ skipping 16 matching lines @@
           'variables': {
             'test_suite_name': 'gpu_unittests',
             'input_shlib_path': '<(SHARED_LIB_DIR)/<(SHARED_LIB_PREFIX)gpu_unittests<(SHARED_LIB_SUFFIX)',
           },
           'includes': [ '../build/apk_test.gypi' ],
         },
       ],
     }],
   ],
 }