Add fetch recipe targeting iOS

Adds support for passing target_os_only to the chromium recipe, and adds
"fetch ios" as an alias for passing both target_os=['ios'] and
target_os_only=True as described in the iOS build instructions page.

BUG=None
R=agable@chromium.org, cmp@chromium.org

Review URL: https://codereview.chromium.org/21428002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@215891 0039d316-1c4b-4281-b951-d872f2087c98

recipes/chromium.py

@@ -34,6 +34,8 @@ class Chromium(recipe_util.Recipe):
       spec['submodule_git_svn_spec'] = props['submodule_git_svn_spec']
     if props.get('target_os'):
       spec['target_os'] = props['target_os'].split(',')
+    if props.get('target_os_only'):
+      spec['target_os_only'] = props['target_os_only']
     checkout_type = 'gclient_git_svn'
     if props.get('nosvn'):
       checkout_type = 'gclient_git'

recipes/ios.py

@@ -0,0 +1,30 @@
+# 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 sys
+
+import recipe_util  # pylint: disable=F0401
+
+
+# This class doesn't need an __init__ method, so we disable the warning
+# pylint: disable=W0232
+class IOS(recipe_util.Recipe):
+  """Basic Recipe alias for iOS -> Chromium."""
+
+  @staticmethod
+  def fetch_spec(props):
+    return {
+      'alias': {
+        'recipe': 'chromium',
+        'props': ['--target_os=ios', '--target_os_only=True'],
+      },
+    }
+
+
+def main(argv=None):
+  return IOS().handle_args(argv)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))