[Signin Error Dialog] (2/3) Added handlers and UI constructors

chrome/browser/ui/webui/signin/get_auth_frame.h

-// Copyright 2016 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.
-
-#ifndef CHROME_BROWSER_UI_WEBUI_SIGNIN_GET_AUTH_FRAME_H_
-#define CHROME_BROWSER_UI_WEBUI_SIGNIN_GET_AUTH_FRAME_H_
-
-#include <string>
-
-namespace content {
-class RenderFrameHost;
-class WebContents;
-}
-
-namespace signin {
-
-// Gets a webview within an auth page that has the specified parent frame name
-// (i.e. <webview name="foobar"></webview>).
-content::RenderFrameHost* GetAuthFrame(content::WebContents* web_contents,
-                                       const std::string& parent_frame_name);
-
-content::WebContents* GetAuthFrameWebContents(
-    content::WebContents* web_contents,
-    const std::string& parent_frame_name);
-
-}  // namespace signin
-
-#endif  // CHROME_BROWSER_UI_WEBUI_SIGNIN_GET_AUTH_FRAME_H_