Factor out uses of the WebContentsModalDialog interface from platform-independent code

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

 // Copyright (c) 2013 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/profile_signin_confirmation_dialog.h"
 
 #include "base/json/json_writer.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_dialogs.h"
@@ skipping 112 matching lines @@
   DCHECK(browser);
   delegate_ = CreateConstrainedWebDialog(
       profile, this, NULL, browser->tab_strip_model()->GetActiveWebContents());
 }
 
 ProfileSigninConfirmationDialog::~ProfileSigninConfirmationDialog() {
 }
 
 void ProfileSigninConfirmationDialog::Close() const {
   closed_by_handler_ = true;
-  delegate_->GetWindow()->CloseWebContentsModalDialog();
+  delegate_->OnDialogCloseFromWebUI();
 }
 
 ui::ModalType ProfileSigninConfirmationDialog::GetDialogModalType() const {
   return ui::MODAL_TYPE_WINDOW;
 }
 
 string16 ProfileSigninConfirmationDialog::GetDialogTitle() const {
   return l10n_util::GetStringUTF16(
       IDS_ENTERPRISE_SIGNIN_PROFILE_LINK_DIALOG_TITLE);
 }
@@ skipping 34 matching lines @@
 void ProfileSigninConfirmationDialog::OnCloseContents(
     content::WebContents* source,
     bool* out_close_dialog) {
   if (out_close_dialog)
     *out_close_dialog = true;
 }
 
 bool ProfileSigninConfirmationDialog::ShouldShowDialogTitle() const {
   return true;
 }