Avoid loading the last used browser profile in app_controller_mac when it's not needed.

apps/app_shim/chrome_main_app_mode_mac.mm

 // Copyright 2013 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 587 matching lines @@
   AppShimController controller;
   base::MessageLoopForUI main_message_loop;
   main_message_loop.set_thread_name("MainThread");
   base::PlatformThread::SetName("CrAppShimMain");
 
   if (pid == -1) {
     // Launch Chrome if it isn't already running.
     ProcessSerialNumber psn;
     CommandLine command_line(CommandLine::NO_PROGRAM);
     command_line.AppendSwitch(switches::kSilentLaunch);
-    command_line.AppendSwitchPath(switches::kProfileDirectory,
-                                  info->profile_dir);
+
+    if (info->app_mode_id == app_mode::kAppListModeId) {
+      command_line.AppendSwitch(switches::kShowAppList);

[Nico, 2014/01/14 02:06:34]

I didn't get why this is needed.

[tapted, 2014/01/14 04:02:28]

Added a comment. This is the "Chrome not running" branch: passing
--show-app-list allows browser startup codepaths to load the best profile.
Otherwise, it's not known until the UI runloop has spun up, and the shim has
connected to the IPC domain socket.

+    } else {
+      command_line.AppendSwitchPath(switches::kProfileDirectory,
+                                    info->profile_dir);
+    }
+
     bool success =
         base::mac::OpenApplicationWithPath(base::mac::OuterBundlePath(),
                                            command_line,
                                            kLSLaunchDefaults,
                                            &psn);
     if (!success)
       return 1;
 
     base::Callback<void(bool)> on_ping_chrome_reply =
         base::Bind(&AppShimController::OnPingChromeReply,
@@ skipping 17 matching lines @@
     // minute.
     main_message_loop.PostTask(
         FROM_HERE,
         base::Bind(&AppShimController::Init,
                    base::Unretained(&controller)));
   }
 
   main_message_loop.Run();
   return 0;
 }