Enable profile switching for standalone App Launcher via the Settings App.

chrome/browser/profiles/profile_manager.h

 // 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.
 
 // This class keeps track of the currently-active profiles in the runtime.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 
 #include <list>
@@ skipping 83 matching lines @@
   FilePath GetInitialProfileDir();
 
   // Get the Profile last used (the Profile to which owns the most recently
   // focused window) with this Chrome build. If no signed profile has been
   // stored in Local State, hand back the Default profile.
   Profile* GetLastUsedProfile(const FilePath& user_data_dir);
 
   // Same as instance method but provides the default user_data_dir as well.
   static Profile* GetLastUsedProfile();
 
+  // Get the path of the last used profile, or if that's undefined, the default
+  // profile.
+  FilePath GetLastUsedProfileDir(const FilePath& user_data_dir);
+
   // Get the Profiles which are currently open, i.e., have open browsers, or
   // were open the last time Chrome was running. The Profiles appear in the
   // order they were opened. The last used profile will be on the list, but its
   // index on the list will depend on when it was opened (it is not necessarily
   // the last one).
   std::vector<Profile*> GetLastOpenedProfiles(const FilePath& user_data_dir);
 
   // Same as instance method but provides the default user_data_dir as well.
   static std::vector<Profile*> GetLastOpenedProfiles();
 
@@ skipping 243 matching lines @@
 class ProfileManagerWithoutInit : public ProfileManager {
  public:
   explicit ProfileManagerWithoutInit(const FilePath& user_data_dir);
 
  protected:
   virtual void DoFinalInitForServices(Profile*, bool) OVERRIDE {}
   virtual void DoFinalInitLogging(Profile*) OVERRIDE {}
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_