Split off histograms.xml from the main metrics WATCHLISTS entry.

I'm finding that I get lots of watchlist spam from histograms.xml changes that
in practice I just ignore.  Therefore, I've split the watchlists entry into two:
one for non-XML files, and one for XML files.

BUG=none
TEST=none
[email protected]

Review URL: https://codereview.chromium.org/168263007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252482 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/WATCHLISTS b/WATCHLISTS
index 32e89e45..fceb8a77 100644
--- a/WATCHLISTS
+++ b/WATCHLISTS
@@ -374,11 +374,16 @@
                   '|chrome/browser/metrics/'\
                   '|chrome/common/metrics/'\
                   '|chrome/browser/chromeos/external_metrics'\
-                  '|chrome/browser/extensions/api/metrics/metrics'\
+                  '|chrome/browser/extensions/api/metrics_private/'\
                   '|chrome/browser/ui/webui/metrics_handler'\
                   '|content/browser/user_metrics.cc'\
                   '|content/public/browser/user_metrics.h'\
-                  '|tools/metrics/'
+                  # Exclude XML files; in particular, histograms.xml.
+                  '|tools/metrics/[^.]*([.](?!xml$).*)?$',
+    },
+    'metrics_xml_files': {
+      # Subscribe to this to watch for changes to histograms.xml.
+      'filepath': 'tools/metrics/.*\.xml$'
     },
     'mojo': {
       'filepath': 'mojo',
@@ -774,6 +779,7 @@
     'metrics': ['[email protected]',
                 '[email protected]',
                 '[email protected]'],
+    'metrics_xml_files': ['[email protected]', '[email protected]'],
     'mojo': ['[email protected]',
              '[email protected]',
              '[email protected]',