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

build/scripts/slave/runhooks_wrapper.py

Index: build/scripts/slave/runhooks_wrapper.py
===================================================================
--- build/scripts/slave/runhooks_wrapper.py	(revision 0)
+++ build/scripts/slave/runhooks_wrapper.py	(working copy)
@@ -0,0 +1,49 @@
+#!/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.
+
+"""Wrapper script for `gclient runhooks`.
+
+This is useful to set slave-dependent gyp defines.
+"""
+
+import optparse
+import os
+import pipes
+import sys
+
+from common import chromium_utils
+
+
+# Path of the scripts/slave/ checkout on the slave, found by looking at the
+# current runhooks_wrapper.py script's path's dirname().
+SLAVE_SCRIPTS_DIR = os.path.dirname(os.path.abspath(__file__))
+# Path of the build/ checkout on the slave, found relative to the
+# scripts/slave/ directory.
+BUILD_DIR = os.path.dirname(os.path.dirname(SLAVE_SCRIPTS_DIR))
+
+
+def main():
+  parser = optparse.OptionParser(description=__doc__)
+  parser.add_option('--use-goma', action='store_true')
+  parser.add_option('--goma-dir',
+                    default=os.path.join(BUILD_DIR, 'goma'),
+                    help='goma directory, only used if --use-goma is passed')
+  options, args = parser.parse_args()
+  assert not args
+
+  if options.use_goma:
+    # Add goma-related GYP_DEFINES if requested. This is done in a slave script
+    # because goma_dir is a slave-relative path and is not known to the master.
+    gyp_defines = os.environ.get('GYP_DEFINES', '')
+    # pipes.quote() is necessary on Windows: http://crbug.com/340918#c7 - 11.
+    gyp_defines += ' use_goma=1 gomadir=' + pipes.quote(options.goma_dir)
+    os.environ['GYP_DEFINES'] = gyp_defines
+    print 'Changed GYP_DEFINES to', os.environ['GYP_DEFINES']
+
+  return chromium_utils.RunCommand(['gclient', 'runhooks'])
+
+
+if '__main__' == __name__:
+  sys.exit(main())