GN: add skia_use_mesa for OSMesa in tools.

infra/bots/recipe_modules/flavor/gn_flavor.py

 # Copyright 2016 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.
 
 import default_flavor
 
 """GN flavor utils, used for building Skia with GN."""
 class GNFlavorUtils(default_flavor.DefaultFlavorUtils):
   def supported(self):
     extra_config = self.m.vars.builder_cfg.get('extra_config', '')
     os           = self.m.vars.builder_cfg.get('os',           '')
     target_arch  = self.m.vars.builder_cfg.get('target_arch',  '')
 
     return any([
       'CT' in extra_config,
       'SAN' in extra_config,
       extra_config == 'Fast',
       extra_config == 'GN',
+      extra_config == 'Mesa',
       extra_config == 'NoGPU',
       extra_config.startswith('SK'),
       os == 'Ubuntu' and target_arch == 'x86',
     ])
 
   def _run(self, title, cmd, env=None, infra_step=False):
     self.m.vars.default_env = {k: v for (k,v)
                                in self.m.vars.default_env.iteritems()
                                if k in ['PATH']}
     self.m.run(self.m.step, title, cmd=cmd,
@@ skipping 28 matching lines @@
       extra_cflags.append('-D' + extra_config)
     if extra_config == 'MSAN':
       extra_ldflags.append('-L' + clang_linux + '/msan')
 
     args = {}
 
     if configuration != 'Debug':
       args['is_debug'] = 'false'
     if extra_config == 'MSAN':
       args['skia_use_fontconfig'] = 'false'
+    if extra_config == 'Mesa':
+      args['skia_use_mesa'] = 'true'
     if extra_config == 'NoGPU':
       args['skia_enable_gpu'] = 'false'
 
     for (k,v) in {
       'cc':  cc,
       'cxx': cxx,
       'extra_cflags':  ' '.join(extra_cflags),
       'extra_ldflags': ' '.join(extra_ldflags),
       'sanitize': extra_config if 'SAN' in extra_config else '',
       'target_cpu': 'x86' if target_arch == 'x86' else '',
@@ skipping 25 matching lines @@
     if 'ASAN' == extra_config:
       env[ 'ASAN_OPTIONS'] = 'symbolize=1 detect_leaks=1'
       env[ 'LSAN_OPTIONS'] = 'symbolize=1 print_suppressions=1'
       env['UBSAN_OPTIONS'] = 'symbolize=1 print_stacktrace=1'
 
     if 'MSAN' == extra_config:
       # Find the MSAN-built libc++.
       env['LD_LIBRARY_PATH'] = clang_linux + '/msan'
 
     self._run(name, cmd, env=env)