[MIPS] Add support for Chromium-Android for MIPS build to BUILD.gn

build/gyp_chromium

 #!/usr/bin/env python
 
 # 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 script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
@@ skipping 120 matching lines @@
   # These tuples of (key, value, gn_arg_string) use the gn_arg_string for
   # gn when the key is set to the given value in the GYP arguments.
   remap_cases = [
       ('branding', 'Chrome', 'is_chrome_branded=true'),
       ('buildtype', 'Official', 'is_official_build=true'),
       ('component', 'shared_library', 'is_component_build=true'),
       ('clang', '1', 'is_clang=true'),
       ('target_arch', 'ia32', 'cpu_arch="x86"'),
       ('target_arch', 'x64', 'cpu_arch="x64"'),
       ('target_arch', 'arm', 'cpu_arch="arm"'),
+      ('target_arch', 'mipsel', 'cpu_arch="mipsel"'),
       ('fastbuild', '0', 'symbol_level=2'),
       ('fastbuild', '1', 'symbol_level=1'),
       ('fastbuild', '2', 'symbol_level=0'),
       ('OS', 'ios', 'os="ios"'),
       ('OS', 'android', 'os="android"'),
       ('chromeos', '1', 'os="chromeos"'),
       ('use_aura', '1', 'use_aura=true'),
       ('asan', '1', 'is_asan=true'),
       ('lsan', '1', 'is_lsan=true'),
   ]
@@ skipping 187 matching lines @@
   # to enfore syntax checking.
   syntax_check = os.environ.get('CHROMIUM_GYP_SYNTAX_CHECK')
   if syntax_check and int(syntax_check):
     args.append('--check')
 
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   # Off we go...
   sys.exit(gyp.main(args))