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

chrome/browser/profiles/profile_manager.cc

Index: chrome/browser/profiles/profile_manager.cc
diff --git a/chrome/browser/profiles/profile_manager.cc b/chrome/browser/profiles/profile_manager.cc
index 714c2883aa4fb51c8e8260838dcdd9d41b9d6c9c..829ee8305c5c2e9cbede2fc7befbace9c7a7e7b5 100644
--- a/chrome/browser/profiles/profile_manager.cc
+++ b/chrome/browser/profiles/profile_manager.cc
@@ -323,6 +323,20 @@ Profile* ProfileManager::GetLastUsedProfile(const FilePath& user_data_dir) {
   return GetProfile(last_used_profile_dir);
 }
 
+Profile* ProfileManager::GetAppListProfile(const FilePath& user_data_dir) {
+  FilePath app_list_profile_dir(user_data_dir);
+  std::string app_list_profile;
+  PrefService* local_state = g_browser_process->local_state();
+  DCHECK(local_state);
+
+  if (local_state->HasPrefPath(prefs::kAppListProfile))
+    app_list_profile = local_state->GetString(prefs::kAppListProfile);
+  app_list_profile_dir = app_list_profile.empty() ?
+      app_list_profile_dir.AppendASCII(chrome::kInitialProfile) :

[tapted, 2013/01/17 04:23:31]

Should this (as an extra step) first check prefs::kProfileLastUsed (perhaps
immediately setting kAppListProfile to that preference)?

This would stop it being recreated if someone deletes their default profile and
switches on the App Launcher. It also gives a default that is more likely to
match the currently running browser the first time it's launched.

[koz (OOO until 15th September), 2013/01/18 05:37:33]

That's a good idea. Done.

+      app_list_profile_dir.AppendASCII(app_list_profile);
+  return GetProfile(app_list_profile_dir);
+}
+
 std::vector<Profile*> ProfileManager::GetLastOpenedProfiles(
     const FilePath& user_data_dir) {
   PrefService* local_state = g_browser_process->local_state();
@@ -840,6 +854,7 @@ void ProfileManager::CreateMultiProfileAsync(
 
 // static
 void ProfileManager::RegisterPrefs(PrefServiceSimple* prefs) {
+  prefs->RegisterStringPref(prefs::kAppListProfile, "");
   prefs->RegisterStringPref(prefs::kProfileLastUsed, "");
   prefs->RegisterIntegerPref(prefs::kProfilesNumCreated, 1);
   prefs->RegisterListPref(prefs::kProfilesLastActive);