Refactor ProcessSingleton so that it may be used distinctly from a full browser process.

chrome/browser/process_singleton.cc

 // 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.
 
 #include "chrome/browser/process_singleton.h"
 
 void ProcessSingleton::Unlock() {
     DCHECK(CalledOnValidThread());
     locked_ = false;
     foreground_window_ = NULL;
     // Replay the command lines of the messages which were received while the
     // ProcessSingleton was locked. Only replay each message once.
     std::set<DelayedStartupMessage> replayed_messages;
     for (std::vector<DelayedStartupMessage>::const_iterator it =
              saved_startup_messages_.begin();
          it != saved_startup_messages_.end(); ++it) {
       if (replayed_messages.find(*it) !=
           replayed_messages.end())
         continue;
-      ProcessCommandLine(CommandLine(it->first), it->second);
+      notification_callback_.Run(CommandLine(it->first), it->second);
       replayed_messages.insert(*it);
     }
     saved_startup_messages_.clear();
 }