Add a check on regular expression check.

BUG=None
TEST=None

Change-Id: I459dc2c3b2e7ee5ff24c1b27bb31121cdace75c6
(cherry picked from commit cbbf69c198f75b56fcb00aaa4b2c13cc000b6ab9)
Reviewed-on: https://chromium-review.googlesource.com/210396
Reviewed-by: Dharani Govindan <dharani@chromium.org>
Tested-by: Dharani Govindan <dharani@chromium.org>
diff --git a/scripts/cros_mark_chrome_as_stable.py b/scripts/cros_mark_chrome_as_stable.py
index 36fbbea..c174786 100644
--- a/scripts/cros_mark_chrome_as_stable.py
+++ b/scripts/cros_mark_chrome_as_stable.py
@@ -134,10 +134,13 @@
   """
   deps_contents = cros_build_lib.RunCommand(['svn', 'cat', url],
                                             redirect_stdout=True).output
-  platforms = re.search(r'buildspec_platforms.*\s.*\s', deps_contents).group()
 
-  if 'chromeos' in platforms or 'all' in platforms:
-    return True
+  platforms_search = re.search(r'buildspec_platforms.*\s.*\s', deps_contents)
+
+  if platforms_search:
+    platforms = platforms_search.group()
+    if 'chromeos' in platforms or 'all' in platforms:
+      return True
 
   return False