Display local signin error without browser and record the path of selected profile in user manager.

chrome/browser/ui/webui/signin/user_manager_screen_handler.cc

Index: chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
diff --git a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
index a56bbe86f0f4b62d786d9c086bb32c4b41c3cbb3..c34c0545d581c08c2d18acfe9f120e07313cd216 100644
--- a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
+++ b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
@@ -469,11 +469,25 @@ void UserManagerScreenHandler::HandleAuthenticatedLaunchUser(
     }
   }
 
-  // In order to support the upgrade case where we have a local hash but no
-  // password token, the user perform a full online reauth.
-  UserManager::ShowReauthDialog(web_ui()->GetWebContents()->GetBrowserContext(),
-                                email_address_,
+  content::BrowserContext* browser_context =
+      web_ui()->GetWebContents()->GetBrowserContext();
+
+// In order to support the upgrade case where we have a local hash but no
+// password token, the user perform a full online reauth.
+// TODO(zmin): Remove the condition for MACOSX once user_manager_mac.cc is
+// updated.
+#if !defined(OS_MACOSX)
+  if (!email_address_.empty()) {
+    UserManager::ShowReauthDialog(browser_context, email_address_,
+                                  signin_metrics::Reason::REASON_UNLOCK);
+  } else {
+    // Fresh sign in via user manager without existing email address.
+    UserManager::ShowSigninDialog(browser_context, profile_path);
+  }
+#else
+  UserManager::ShowReauthDialog(browser_context, email_address_,
                                 signin_metrics::Reason::REASON_UNLOCK);
+#endif
 }
 
 void UserManagerScreenHandler::HandleRemoveUser(const base::ListValue* args) {