Signing out forces the lock bit to be removed.

Since sync may cause a profile to become signed out, we cannot assume
a signing out profile is unlocked. Thus, forcibly unlock it.

BUG=426174

Review URL: https://codereview.chromium.org/698543002

Cr-Commit-Position: refs/heads/master@{#302427}

chrome/browser/signin/chrome_signin_client.cc

@@ -168,6 +168,7 @@ void ChromeSigninClient::OnSignedOut() {
       g_browser_process->profile_manager()->GetProfileInfoCache();
   size_t index = cache.GetIndexOfProfileWithPath(profile_->GetPath());
   cache.SetLocalAuthCredentialsOfProfileAtIndex(index, std::string());
+  cache.SetProfileSigninRequiredAtIndex(index, false);
 }
 
 net::URLRequestContextGetter* ChromeSigninClient::GetURLRequestContext() {