[watchlists] Added parser watchlist.

Bug: 
Change-Id: I335a793d28697092c89e588c456f2689e689c841
Reviewed-on: https://chromium-review.googlesource.com/494054
Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45060}

WATCHLISTS

@@ -72,7 +72,11 @@
     },
     'value_serializer': {
       'filepath': 'src/value-serializer',
-    }
+    },
+    'parser': {
+      'filepath': 'src/ast/' \
+                  '|src/parsing/',
+    },
   },
 
   'WATCHLISTS': {
@@ -114,5 +118,8 @@
     'value_serializer': [
       'jbroman+watch@chromium.org',
     ],
+    'parser': [
+      'marja+watch@chromium.org',
+    ]
   },
 }