Update histogram values ENUM_BOUNDARY comment.

The new comment tells the committer to update histogram.xml when adding a new
value. The PRESUBMIT and its tests also need to be updated as the enum end
marker is changed.

TEST=updated PRESUBMIT tests
[email protected], [email protected]

Review URL: https://codereview.chromium.org/178143003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253055 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_function_histogram_value.h b/chrome/browser/extensions/extension_function_histogram_value.h
index 72614ac..b30c15c3 100644
--- a/chrome/browser/extensions/extension_function_histogram_value.h
+++ b/chrome/browser/extensions/extension_function_histogram_value.h
@@ -748,7 +748,9 @@
   ACTIVITYLOGPRIVATE_DELETEACTIVITIES,
   NETWORKINGPRIVATE_SETWIFITDLSENABLEDSTATE,
   NETWORKINGPRIVATE_GETWIFITDLSSTATUS,
-  ENUM_BOUNDARY  // Last entry: Add new entries above.
+  // Last entry: Add new entries above and ensure to update
+  // tools/metrics/histograms/histograms/histograms.xml.
+  ENUM_BOUNDARY
 };
 
 }  // namespace functions