Add Physical Web UMA for ListUrlsActivity referers

tools/metrics/actions/actions.xml

 <!--
 Copyright 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is a comprehensive list of Chrome user actions along with the owner
 and description for each user action. A user action should be tied to an actual
 action taken by a user. It should be logged immediately after a user takes the
@@ skipping 11433 matching lines @@
   </description>
 </action>
 
 <action name="PhysicalWeb.NotificationPressed">
   <owner>cco3@chromium.org</owner>
   <owner>mattreynolds@chromium.org</owner>
   <owner>mmocny@chromium.org</owner>
   <description>
     A notification advertising nearby Physical Web URLs was pressed.
   </description>
+  <obsolete>Replaced by the histogram PhysicalWeb.ActivityReferral</obsolete>
 </action>
 
 <action name="PhysicalWeb.OptIn.DeclineButtonPressed">
   <owner>cco3@chromium.org</owner>
   <owner>mattreynolds@chromium.org</owner>
   <owner>mmocny@chromium.org</owner>
   <description>
     The user has disabled the Physical Web feature via the settings.
   </description>
 </action>
@@ skipping 2579 matching lines @@
 <action name="webapps.AddShortcut.Manifest">
   <owner>mlamouri@chromium.org</owner>
   <description>
     Shortcut added to the homescreen with a valid Manifest. This action will be
     recorded in addition to AppShortcut, AppShortcutApple and Bookmark actions
     to keep a trend of whether the webapp also add meta tags.
   </description>
 </action>
 
 </actions>