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

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

-// 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.
-
-#include "chrome/browser/ui/webui/signin/get_auth_frame.h"
-
-#include <set>
-
-#include "base/bind.h"
-#include "components/guest_view/browser/guest_view_manager.h"
-#include "content/public/browser/web_contents.h"
-#include "extensions/browser/guest_view/web_view/web_view_guest.h"
-
-namespace {
-
-bool AddWebContentsToSet(std::set<content::WebContents*>* frame_set,
-                         const std::string& web_view_name,
-                         content::WebContents* web_contents) {
-  auto* web_view = extensions::WebViewGuest::FromWebContents(web_contents);
-  if (web_view && web_view->name() == web_view_name)
-    frame_set->insert(web_contents);
-  return false;
-}
-
-}  // namespace
-
-namespace signin {
-
-content::RenderFrameHost* GetAuthFrame(content::WebContents* web_contents,
-                                       const std::string& parent_frame_name) {
-  content::WebContents* auth_web_contents =
-      GetAuthFrameWebContents(web_contents, parent_frame_name);
-  return auth_web_contents ? auth_web_contents->GetMainFrame() : nullptr;
-}
-
-content::WebContents* GetAuthFrameWebContents(
-    content::WebContents* web_contents,
-    const std::string& parent_frame_name) {
-  std::set<content::WebContents*> frame_set;
-  auto* manager = guest_view::GuestViewManager::FromBrowserContext(
-      web_contents->GetBrowserContext());
-  if (manager) {
-    manager->ForEachGuest(
-        web_contents,
-        base::Bind(&AddWebContentsToSet, &frame_set, parent_frame_name));
-  }
-  DCHECK_GE(1U, frame_set.size());
-  if (!frame_set.empty())
-    return *frame_set.begin();
-
-  return nullptr;
-}
-
-}  // namespace signin