Add histogram for pages to open enum on session restore.

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 12803 matching lines @@
   </summary>
 </histogram>
 
 <histogram name="Settings.HomePageIsNewTabPage" enum="Boolean">
   <summary>
     Whether or not the home page user preference is set to the default NTP value
     when a profile is loaded.
   </summary>
 </histogram>
 
+<histogram name="Settings.SessionRestoreOnStartup" enum="StartupPagePref">
+  <summary>Records startup page settings when a profile is loaded.</summary>
+</histogram>
+
 <histogram name="Settings.ShowHomeButton" enum="BooleanEnabled">
   <summary>
     Whether or not the Home button is enabled in user preferences when a profile
     is loaded.
   </summary>
 </histogram>
 
 <histogram name="SimpleCache.CheckCRCResult" enum="CheckCRCResult">
   <summary>
     Whether or not the CRC was checked at the moment when the last reference to
@@ skipping 8381 matching lines @@
   <int value="49316" label="TLS_PSK_WITH_AES_128_CCM"/>
   <int value="49317" label="TLS_PSK_WITH_AES_256_CCM"/>
   <int value="49318" label="TLS_DHE_PSK_WITH_AES_128_CCM"/>
   <int value="49319" label="TLS_DHE_PSK_WITH_AES_256_CCM"/>
   <int value="49320" label="TLS_PSK_WITH_AES_128_CCM_8"/>
   <int value="49321" label="TLS_PSK_WITH_AES_256_CCM_8"/>
   <int value="49322" label="TLS_PSK_DHE_WITH_AES_128_CCM_8"/>
   <int value="49323" label="TLS_PSK_DHE_WITH_AES_256_CCM_8"/>
 </enum>
 
+<enum name="StartupPagePref" type="int">
+  <int value="0" label="None"/>
+  <int value="1" label="Open homepage (unused)"/>
+  <int value="2" label="Open new tab page"/>
+  <int value="3" label="Continue from last opened pages"/>
+  <int value="4" label="Open zero URLs"/>
+  <int value="5" label="Open one URL"/>
+  <int value="6" label="Open multiple URLs"/>
+</enum>
+
 <enum name="SuspendStatus" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="Failure"/>
   <int value="2" label="Cancelled"/>
   <int value="3" label="Attempted"/>
 </enum>
 
 <enum name="TabRestoreUserAction" type="int">
   <int value="0" label="Wait for completion"/>
   <int value="1" label="Leave tab (close tab/switch tab/go to tab switcher)"/>
@@ skipping 2503 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>