Do not start goma in ChromeOS gclient runhook if gomadir is given.

scripts/slave/recipe_modules/chromium/api.py

 # Copyright 2013 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 re
 
 from recipe_engine import recipe_api
 from recipe_engine import util as recipe_util
 
 class TestLauncherFilterFileInputPlaceholder(recipe_util.InputPlaceholder):
@@ skipping 458 matching lines @@
         self.m.depot_tools.cros_path, 'chrome-sdk',
         '--board=%s' % (self.c.TARGET_CROS_BOARD,),
         '--nocolor',]
     wrapper += self.c.cros_sdk.args
     if self.c.cros_sdk.external:
       wrapper += ['--use-external-config']
     if clean:
       wrapper += ['--clear-sdk-cache']
     if self.c.compile_py.goma_dir:
       wrapper += ['--gomadir', self.c.compile_py.goma_dir]
+      # Since we are very sure api.chromium.compile starts compiler_proxy,
+      # and starting compiler_proxy here make it difficult for us to
+      # investigate the compiler_proxy start-up failure reason,
+      # let me stop starting compiler_proxy. (crbug.com/639432)
+      wrapper += ['--nostart-goma']
     if self.c.gyp_env.GYP_DEFINES.get('fastbuild', 0) == 1:
       wrapper += ['--fastbuild']
     wrapper += ['--']
     return wrapper
 
   def ensure_goma(self, canary=False):
     goma_dir = self.m.goma.ensure_goma(canary=canary)
     if goma_dir:
       # TODO(phajdan.jr): goma_dir should always be non-empty.
       self.c.gyp_env.GYP_DEFINES['gomadir'] = goma_dir
@@ skipping 315 matching lines @@
       }))
 
   def get_annotate_by_test_name(self, test_name):
     return 'graphing'
 
   def download_lto_plugin(self):
     return self.m.python(
         name='download LTO plugin',
         script=self.m.path['checkout'].join(
             'build', 'download_gold_plugin.py'))