Set use_goma=1 and gomadir=path in GYP_DEFINES on master.

build/scripts/master/factory/chromium_factory.py

Index: build/scripts/master/factory/chromium_factory.py
===================================================================
--- build/scripts/master/factory/chromium_factory.py	(revision 245768)
+++ build/scripts/master/factory/chromium_factory.py	(working copy)
@@ -39,8 +39,8 @@
     gclient_env: a dict for gclient_env.
   """
   options = options or {}
-  if (not '--compiler=goma' in options and
-      not '--compiler=goma-clang' in options):
+  if ('--compiler=goma' not in options and
+      '--compiler=goma-clang' not in options):
     return
   gyp_defines = gclient_env.get('GYP_DEFINES', '')
   # goma couldn't work with pdbserv.
@@ -55,6 +55,20 @@
   gclient_env['GYP_DEFINES'] = gyp_defines
 
 
+def SetGomaGypDefines(options, target, gclient_env):
+  """Adds goma flags to GYP_DEFINES."""
+  options = options or {}
+  if ('--compiler=goma' not in options and
+      '--compiler=goma-clang' not in options):
+    return
+  # Starting from e.g. C:\b\build\slave\build_slave_path\build, find
+  # C:\b\build\goma.
+  gomadir = os.path.normpath(os.path.join('..', '..', '..', 'goma'))
+  gyp_defines = gclient_env.get('GYP_DEFINES', '')
+  gyp_defines += ' use_goma=1 gomadir=%s' % gomadir
+  gclient_env['GYP_DEFINES'] = gyp_defines
+
+
 class ChromiumFactory(gclient_factory.GClientFactory):
   """Encapsulates data and methods common to the chromium master.cfg files."""
 
@@ -954,6 +968,7 @@
     if self._target_platform == 'win32':
       factory_properties['gclient_env'].setdefault('GYP_MSVS_VERSION', '2010')
       FixForGomaWin(options, target, factory_properties['gclient_env'])
+    SetGomaGypDefines(options, target, factory_properties['gclient_env']):
     tests = tests or []
 
     if factory_properties.get('needs_valgrind'):