Update cq_client and add validate command to commit_queue binary

commit_queue.py

Index: commit_queue.py
diff --git a/commit_queue.py b/commit_queue.py
index b08d4fec7ccff426c3d4dd241ff5ed6273e5b16d..25ddb38127df55b553238c65af7bcde78d794c3a 100755
--- a/commit_queue.py
+++ b/commit_queue.py
@@ -26,6 +26,7 @@ THIRD_PARTY_DIR = os.path.join(os.path.dirname(__file__), 'third_party')
 sys.path.insert(0, THIRD_PARTY_DIR)
 
 from cq_client import cq_pb2
+from cq_client import validate_config
 from protobuf26 import text_format
 
 def usage(more):
@@ -143,6 +144,25 @@ def CMDbuilders(parser, args):
 
 CMDbuilders.func_usage_more = '<path-to-cq-config>'
 
+
+def CMDvalidate(parser, args):
+  """Validates a CQ config.
+
+  Takes a single argument - path to the CQ config to be validated. Returns 0 on
+  valid config, non-zero on invalid config. Errors and warnings are printed to
+  screen.
+  """
+  _, args = parser.parse_args(args)
+  if len(args) != 1:
+    parser.error('Expected a single path to CQ config. Got: %s' %
+                 ' '.join(args))
+
+  with open(args[0]) as config_file:
+    cq_config = config_file.read()
+  return 0 if validate_config.IsValid(cq_config) else 1
+
+CMDvalidate.func_usage_more = '<path-to-cq-config>'
+
 ###############################################################################
 ## Boilerplate code