Add UMA tracking to "Recently Closed" submenu.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 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 used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 10325 matching lines @@
   </summary>
 </histogram>
 
 <histogram name="WinTimeTicks.VersionTotal" enum="WindowsVersion">
   <summary>
     The number of times the TimeTicks field trial ran for comparison with
     WinTimeTicks.VersionSuccess. Broken down by Windows version.
   </summary>
 </histogram>
 
+<histogram name="WrenchMenu.RecentTabsSubMenu" enum="RecentTabsAction">
+  <summary>
+    The number of times each tab or window restore option in the Recent Tabs
+    submenu is clicked.
+  </summary>
+</histogram>
+
 <histogram name="ZeroSuggest.AllResults">
   <summary>
     The number of results (either query or URL) from ZeroSuggest. This is set
     every time a successful response from ZeroSuggest is recieved, which can be
     every time the user focuses on the omnibox.
   </summary>
 </histogram>
 
 <histogram name="ZeroSuggest.QueryResults">
   <summary>
@@ skipping 4333 matching lines @@
   <int value="22" label="DOMAIN_NUM_EVENTS"/>
 </enum>
 
 <enum name="QuicHandshakeState" type="int">
   <int value="0" label="STARTED"/>
   <int value="1" label="ENCRYPTION_ESTABLISHED"/>
   <int value="2" label="HANDSHAKE_CONFIRMED"/>
   <int value="3" label="FAILED"/>
 </enum>
 
+<enum name="RecentTabsAction" type="int">
+  <int value="0" label="Local Session Tab"/>
+  <int value="1" label="Other Device Tab"/>
+  <int value="2" label="Restore Window"/>
+  <int value="3" label="Show More"/>
+</enum>
+
 <enum name="ResolutionCategory" type="int">
   <int value="0" label="RESOLVE_SUCCESS"/>
   <int value="1" label="RESOLVE_FAIL"/>
   <int value="2" label="RESOLVE_SPECULATIVE_SUCCESS"/>
   <int value="3" label="RESOLVE_SPECULATIVE_FAIL"/>
 </enum>
 
 <enum name="ResolutionUnspecWasteCategory" type="int">
   <int value="0" label="AF_WASTE_IPV4_ONLY">
     Running in a IPv4-only configuration.  No waste.
@@ skipping 2469 matching lines @@
   <group name="Disabled" label="Neither extra webstore link is visible"/>
   <group name="FooterLink" label="Link in bottom right of footer"/>
   <group name="PlusIcon" label="Plus icon in apps page"/>
   <affected-histogram name="Extensions.AppLaunch"/>
   <affected-histogram name="NewTabPage.DefaultPageType"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>