After locking a profile and showing the User Manager, make Guest the active profile

chrome/browser/profiles/profiles_state.cc

 // 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.
 
 #include "chrome/browser/profiles/profiles_state.h"
 
 #include "base/files/file_path.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 138 matching lines @@
   DCHECK(profile);
   GAIAInfoUpdateServiceFactory::GetInstance()->GetForProfile(profile)->Update();
 }
 
 SigninErrorController* GetSigninErrorController(Profile* profile) {
   ProfileOAuth2TokenService* token_service =
       ProfileOAuth2TokenServiceFactory::GetForProfile(profile);
   return token_service ? token_service->signin_error_controller() : NULL;
 }
 
+void SetActiveProfileToGuestIfLocked() {
+  Profile* active_profile = ProfileManager::GetLastUsedProfile();
+  DCHECK(active_profile);
+
+  ProfileManager* profile_manager = g_browser_process->profile_manager();
+  ProfileInfoCache& cache = profile_manager->GetProfileInfoCache();

[Alexei Svitkine (slow), 2014/09/19 15:33:36]

Nit: Const ref or ptr, please.

[noms (inactive), 2014/09/22 15:39:45]

Done.

+  size_t index = cache.GetIndexOfProfileWithPath(active_profile->GetPath());
+  if (!cache.ProfileIsSigninRequiredAtIndex(index))
+    return;
+
+  // The guest profile must have been loaded already.
+  Profile* guest_profile = profile_manager->GetProfile(
+      ProfileManager::GetGuestProfilePath());
+  CHECK(guest_profile);
+
+  PrefService* local_state = g_browser_process->local_state();
+  DCHECK(local_state);
+  local_state->SetString(prefs::kProfileLastUsed,
+                         guest_profile->GetPath().BaseName().MaybeAsASCII());
+}
+
 }  // namespace profiles