bug#112213 -adding timeline pref to mailnews; sr=mscott

mailnews/mailnews.js

@@ -35,6 +35,9 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
+//mailnews.timeline_is_enabled should be set to true ONLY for perf measurement-timeline builds.
+pref("mailnews.timeline_is_enabled", false);
+
 pref("mailnews.logComposePerformance", false);
 
 pref("mail.wrap_long_lines",                true);

modules/libpref/src/init/mailnews.js

@@ -35,6 +35,9 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
+//mailnews.timeline_is_enabled should be set to true ONLY for perf measurement-timeline builds.
+pref("mailnews.timeline_is_enabled", false);
+
 pref("mailnews.logComposePerformance", false);
 
 pref("mail.wrap_long_lines",                true);