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 the shim is the app launcher, pass --show-app-list when starting a new
+    // Chrome process to inform startup codepaths and load the correct profile.
+    if (info->app_mode_id == app_mode::kAppListModeId) {
+      command_line.AppendSwitch(switches::kShowAppList);
+    } 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;
 }