Replace remaining shell references with service manager

mash/session/session.cc

 // Copyright 2015 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 "mash/session/session.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "mash/login/public/interfaces/login.mojom.h"
@@ skipping 111 matching lines @@
   connections_.erase(connection);
 }
 
 void Session::StartRestartableService(
     const std::string& url,
     const base::Closure& restart_callback) {
   // TODO(beng): This would be the place to insert logic that counted restarts
   //             to avoid infinite crash-restart loops.
   std::unique_ptr<service_manager::Connection> connection =
       connector()->Connect(url);
-  // Note: |connection| may be null if we've lost our connection to the shell.
+  // Note: |connection| may be null if we've lost our connection to the service
+  // manager.
   if (connection) {
     connection->SetConnectionLostClosure(
         base::Bind(&LogAndCallServiceRestartCallback, url, restart_callback));
     connections_[url] = std::move(connection);
   }
 }
 
 }  // namespace session
 }  // namespace main