cros: Add enterprise user session metrics

chrome/common/pref_names.h

 // Copyright (c) 2012 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.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
@@ skipping 244 matching lines @@
 extern const char kDisplayProperties[];
 extern const char kSecondaryDisplays[];
 extern const char kDisplayRotationLock[];
 extern const char kEnableStylusTools[];
 extern const char kLaunchPaletteOnEjectEvent[];
 extern const char kNoteTakingAppId[];
 extern const char kSessionUserActivitySeen[];
 extern const char kSessionStartTime[];
 extern const char kSessionLengthLimit[];
 extern const char kSessionWaitForInitialUserActivity[];
+extern const char kLastSessionType[];
+extern const char kLastSessionLength[];
 extern const char kPowerAcScreenDimDelayMs[];
 extern const char kPowerAcScreenOffDelayMs[];
 extern const char kPowerAcScreenLockDelayMs[];
 extern const char kPowerAcIdleWarningDelayMs[];
 extern const char kPowerAcIdleDelayMs[];
 extern const char kPowerBatteryScreenDimDelayMs[];
 extern const char kPowerBatteryScreenOffDelayMs[];
 extern const char kPowerBatteryScreenLockDelayMs[];
 extern const char kPowerBatteryIdleWarningDelayMs[];
 extern const char kPowerBatteryIdleDelayMs[];
@@ skipping 614 matching lines @@
 extern const char kBookmarksBubbleIOSPromoDismissed[];
 extern const char kNumberBookmarksFootNoteIOSPromoShown[];
 extern const char kBookmarksFootNoteIOSPromoDismissed[];
 extern const char kNumberHistoryPageIOSPromoShown[];
 extern const char kHistoryPageIOSPromoDismissed[];
 #endif
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_