Add policy for limiting the session length

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 0cd51ffd1b2c14ccb9795defff27df51b717ef0c..cc7f69cb5aa25a5582345f66e5c3a22e8ce49382 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -66,6 +66,20 @@ const char kURLsToRestoreOnStartup[] = "session.urls_to_restore_on_startup";
 // higher.
 const char kRestoreOnStartupMigrated[] = "session.restore_on_startup_migrated";
 
+#if defined(OS_CHROMEOS)
+// A preference to keep track of the session start time. The value is set
+// after login. When the browser restarts after a crash, the pref value is not
+// changed unless it appears corrupted (value unset, value lying in the future,
+// zero value).
+const char kSessionStartTime[] = "session.start_time";
+
+// Holds the maximum session time in milliseconds. If this pref is set, the
+// user is logged out when the maximum session time is reached. The user is
+// informed about the remaining time by a countdown timer shown in the ash
+// system tray.
+const char kSessionLengthLimit[] = "session.length_limit";
+#endif
+
 // Disables screenshot accelerators and extension APIs.
 // This setting resides both in profile prefs and local state. Accelerator
 // handling code reads local state, while extension APIs use profile pref.