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

chrome/browser/profiles/profiles_state.cc

Index: chrome/browser/profiles/profiles_state.cc
diff --git a/chrome/browser/profiles/profiles_state.cc b/chrome/browser/profiles/profiles_state.cc
index 2a254993e1c8b363d3941bca7913cca7cdcfb58a..ade8c705fb1b4aadc43afaff466ecd3b9d692185 100644
--- a/chrome/browser/profiles/profiles_state.cc
+++ b/chrome/browser/profiles/profiles_state.cc
@@ -156,4 +156,25 @@ SigninErrorController* GetSigninErrorController(Profile* 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