Expose ARC++ version in metadata.json.

Expose ARC++ version and properly pass it from the master to slave
PFQ builders.

BUG=chromium:587927
TEST=cbuildbot_unittest
TEST=cbuildbot --local -p 'chromiumos/chromite' master-android-pfq
TEST=cbuildbot -p 'chromiumos/chromite' --buildbot --debug --nobootstrap --noreexec --buildroot /source3/buildbot-buildroot master-android-pfq

Change-Id: I86af19e766ad2044334fc837613eaa283e5838b2
Reviewed-on: https://chromium-review.googlesource.com/328847
Commit-Ready: David Riley <davidriley@chromium.org>
Tested-by: David Riley <davidriley@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
diff --git a/scripts/cbuildbot.py b/scripts/cbuildbot.py
index 97fb0ff..ffd329b 100644
--- a/scripts/cbuildbot.py
+++ b/scripts/cbuildbot.py
@@ -317,15 +317,6 @@
   parser.values.chrome_root = value
 
 
-def _CheckChromeRevOption(_option, _opt_str, value, parser):
-  """Validate the chrome_rev option."""
-  value = value.strip()
-  if value not in constants.VALID_CHROME_REVISIONS:
-    raise optparse.OptionValueError('Invalid chrome rev specified')
-
-  parser.values.chrome_rev = value
-
-
 def FindCacheDir(_parser, _options):
   return None
 
@@ -413,9 +404,12 @@
                          'multiple copies of chromite. All these checkouts '
                          'will be contained in the directory specified here. '
                          'Default:%s' % osutils.GetGlobalTempDir())
-  parser.add_remote_option('--chrome_rev', default=None, type='string',
-                           action='callback', dest='chrome_rev',
-                           callback=_CheckChromeRevOption,
+  parser.add_remote_option('--android_rev', default=None, type='choice',
+                           choices=constants.VALID_ANDROID_REVISIONS,
+                           help=('Revision of Android to use, of type [%s]'
+                                 % '|'.join(constants.VALID_ANDROID_REVISIONS)))
+  parser.add_remote_option('--chrome_rev', default=None, type='choice',
+                           choices=constants.VALID_CHROME_REVISIONS,
                            help=('Revision of Chrome to use, of type [%s]'
                                  % '|'.join(constants.VALID_CHROME_REVISIONS)))
   parser.add_remote_option('--profile', default=None, type='string',