Start app shim when app launched.

chrome/app/chrome_main_app_mode_mac.mm

 // 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.
 
 // On Mac, one can't make shortcuts with command-line arguments. Instead, we
 // produce small app bundles which locate the Chromium framework and load it,
 // passing the appropriate data. This is the entry point into the framework for
 // those app bundles.
 
 #import <Cocoa/Cocoa.h>
@@ skipping 69 matching lines @@
     Quit();
     return;
   }
 
   base::FilePath socket_path =
       user_data_dir.Append(app_mode::kAppShimSocketName);
   IPC::ChannelHandle handle(socket_path.value());
   channel_ = new IPC::ChannelProxy(handle, IPC::Channel::MODE_NAMED_CLIENT,
       this, g_io_thread->message_loop_proxy());
 
+  if (CommandLine::ForCurrentProcess()->HasSwitch(app_mode::kNoLaunchApp))
+    return;

[tapted, 2013/05/21 08:33:25]

Since we're going down this path, it still needs to send a message, otherwise
the shim host won't know what extension it's hosting in order to close it when
the extension is unloaded.

You should be able to change AppShimHostMsg_LaunchApp to have a third, bool
argument indicating to the host whether it should launch, or just register
itself with the shimhandler (which will also need that flag, or a new method on
the abstract interface). So, we should get that other change landed first, then
base this change off it to add the "just register" flag.

And, I think editing the existing message is preferable to the alternative of a
new, 'SilentLaunchApp' message, since it's extensible to more/non-orthogonal
flags later.

[jackhou1, 2013/05/28 06:50:33]

Done.

+
   channel_->Send(new AppShimHostMsg_LaunchApp(
       g_info->profile_dir.value(), g_info->app_mode_id));
 }
 
 bool AppShimController::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(AppShimController, message)
     IPC_MESSAGE_HANDLER(AppShimMsg_LaunchApp_Done, OnLaunchAppDone)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
@@ skipping 198 matching lines @@
   // fully initialized don't receive a reply until its run loop starts. Once
   // the reply is received, Chrome will have opened its IPC port, guaranteed.
   [ReplyEventHandler pingProcess:psn andCall:base::Bind(&OnPingChromeReply)];
 
   base::MessageLoopForUI main_message_loop;
   main_message_loop.set_thread_name("MainThread");
   base::PlatformThread::SetName("CrAppShimMain");
   main_message_loop.Run();
   return 0;
 }