cros: Add enterprise user session metrics

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 858c0007022b6d9e7e9aa99ca2f5e3cefab8275d..e2f3df777949b2a97d383ce4912a40f6627d85c0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -14165,6 +14165,32 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Enterprise.PublicSession.SessionLength" units="minutes">
+  <owner>xiyuan@chromium.org</owner>
+  <owner>sduraisamy@chromium.org</owner>
+  <summary>
+    A public session starts when a user signs in using the policy configured
+    public account. It stops when the user signs out. Session length is the
+    duration between the start and stop events. It is recorded during signing
+    out and reported on the next chrome run. This metric tracks the recorded
+    session length rounded down to the nearest 10-minute bucket and capped at 24
+    hours.
+  </summary>
+</histogram>
+
+<histogram name="Enterprise.RegularUserSession.SessionLength" units="minutes">
+  <owner>xiyuan@chromium.org</owner>
+  <owner>sduraisamy@chromium.org</owner>
+  <summary>
+    A regular user session starts when a user signs in using his/her user
+    account. It stops when the user signs out. Session length is the duration
+    between the start and stop events. It is recorded during signing out and
+    reported on the next chrome run. This metric tracks the recorded session
+    length on an enrolled device rouned down to the nearest 10-minute bucket and
+    capped at 24 hours.
+  </summary>
+</histogram>
+
 <histogram name="Enterprise.SystemLogPIILeak" enum="SystemLogPIIType">
   <obsolete>
     Deprecated and removed from code as of 01/2016.
@@ -14282,6 +14308,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Enterprise.UserSession.Logins"
+    enum="EnterpriseUserSessionLogins">
+  <owner>xiyuan@chromium.org</owner>
+  <owner>sduraisamy@chromium.org</owner>
+  <summary>Tracks the sign-in events on an enrolled device.</summary>
+</histogram>
+
 <histogram name="Enterprise.UserSigninChoice" enum="SigninChoice">
   <owner>atwilson@chromium.org</owner>
   <summary>
@@ -86890,6 +86923,18 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="11" label="Request interrupted"/>
 </enum>
 
+<enum name="EnterpriseUserSessionLogins" type="int">
+  <summary>
+    Types of sign-in events as defined in
+    chrome/browser/chromeos/login/enterprise_user_session_metrics.h
+  </summary>
+  <int value="0" label="Regular user"/>
+  <int value="1" label="Manual public session"/>
+  <int value="2" label="Automatic public session"/>
+  <int value="3" label="Manual kiosk session"/>
+  <int value="4" label="Automatic kiosk session"/>
+</enum>
+
 <enum name="ErrorCodesGetAdaptersAddresses" type="int">
   <int value="8" label="ERROR_NOT_ENOUGH_MEMORY"/>
   <int value="87" label="ERROR_INVALID_PARAMETER"/>