Add UMA metric for "View Original" link clicks in distilled page viewer.

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.
 
@@ skipping 2454 matching lines @@
   <owner>yfriedman@chromium.org</owner>
   <description>User opens a distilled page.</description>
 </action>
 
 <action name="DomDistiller_DistilledPagePrefsOpened">
   <owner>smaslo@chromium.org</owner>
   <owner>yfriedman@chromium.org</owner>
   <description>User opens distilled page preferences.</description>
 </action>
 
+<action name="DomDistiller_ViewOriginal">
+  <owner>yfriedman@chromium.org</owner>
+  <description>
+    Records clicks on the &quot;View Original&quot; link in the distilled page
+    viewer.
+  </description>
+</action>
+
 <action name="Duplicate">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="EasyUnlock_Enabled_Disable">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of the metric.</description>
 </action>
 
@@ skipping 8999 matching lines @@
     apple-mobile-webapp-capable meta tag.
   </description>
 </action>
 
 <action name="webapps.AddShortcut.Bookmark">
   <owner>dfalcantara@chromium.org</owner>
   <description>Shortcut added to the homescreen for a bookmark.</description>
 </action>
 
 </actions>