Delete the GTK+ port of Chrome.

tools/gn/bootstrap/bootstrap.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Bootstraps gn.
 
 It is done by first building it manually in a temporary directory, then building
 it with its own BUILD.gn to the final destination.
 """
@@ skipping 222 matching lines @@
         'tool': 'cxx',
     }
     static_libraries['base']['sources'].extend([
         'base/base_paths_posix.cc',
         'base/debug/debugger_posix.cc',
         'base/debug/stack_trace_posix.cc',
         'base/file_util_posix.cc',
         'base/files/file_enumerator_posix.cc',
         'base/files/file_posix.cc',
         'base/message_loop/message_pump_glib.cc',
-        'base/message_loop/message_pump_gtk.cc',
         'base/message_loop/message_pump_libevent.cc',
         'base/nix/xdg_util.cc',
         'base/posix/file_descriptor_shuffle.cc',
         'base/process/internal_linux.cc',
         'base/process/kill_posix.cc',
         'base/process/process_handle_linux.cc',
         'base/process/process_handle_posix.cc',
         'base/process/process_iterator_linux.cc',
         'base/process/process_linux.cc',
         'base/process/process_metrics_linux.cc',
@@ skipping 66 matching lines @@
   if not debug:
     cmd.append('--args=is_debug=false')
   check_call(cmd)
   check_call(['ninja', '-C', build_dir, 'gn'])
   if not debug:
     check_call(['strip', os.path.join(build_dir, 'gn')])
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))