Revert 111695 - Have content/ create and destroy its own threads.

chrome/browser/browser_shutdown.h

Index: chrome/browser/browser_shutdown.h
===================================================================
--- chrome/browser/browser_shutdown.h	(revision 111697)
+++ chrome/browser/browser_shutdown.h	(working copy)
@@ -34,19 +34,14 @@
 // Get the current shutdown type.
 ShutdownType GetShutdownType();
 
-// Performs the shutdown tasks that need to be done before
-// BrowserProcess and the various threads go away.
-//
-// Returns true if the session should be restarted.
-bool ShutdownPreThreadsStop();
+// Invoked in two ways:
+// . When the last browser has been deleted and the message loop has finished
+//   running.
+// . When ChromeFrame::EndSession is invoked and we need to do cleanup.
+//   NOTE: in this case the message loop is still running, but will die soon
+//         after this returns.
+void Shutdown();
 
-// Performs the remaining shutdown tasks after all threads but the
-// main thread have been stopped.  This includes deleting g_browser_process.
-//
-// The provided parameter indicates whether a preference to restart
-// the session was present.
-void ShutdownPostThreadsStop(bool restart_last_session);
-
 // Called at startup to create a histogram from our previous shutdown time.
 void ReadLastShutdownInfo();