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

chrome/browser/ui/webui/tab_modal_confirm_dialog_webui.cc

 // Copyright (c) 2012 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/tab_modal_confirm_dialog_webui.h"
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 36 matching lines @@
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   content::WebUIDataSource* data_source = content::WebUIDataSource::Create(
       chrome::kChromeUITabModalConfirmDialogHost);
   data_source->SetDefaultResource(IDR_TAB_MODAL_CONFIRM_DIALOG_HTML);
   data_source->DisableContentSecurityPolicy();
   content::WebUIDataSource::Add(profile, data_source);
 
   constrained_web_dialog_delegate_ =
       CreateConstrainedWebDialog(profile, this, NULL, web_contents);
-  delegate_->set_window(constrained_web_dialog_delegate_->GetWindow());
+  delegate_->set_close_delegate(this);
 }
 
 ui::ModalType TabModalConfirmDialogWebUI::GetDialogModalType() const {
   return ui::MODAL_TYPE_WINDOW;
 }
 
 string16 TabModalConfirmDialogWebUI::GetDialogTitle() const {
   return delegate_->GetTitle();
 }
 
@@ skipping 21 matching lines @@
 
 void TabModalConfirmDialogWebUI::OnDialogClosed(
     const std::string& json_retval) {
   bool accepted = false;
   if (!json_retval.empty()) {
     scoped_ptr<Value> value(base::JSONReader::Read(json_retval));
     if (!value.get() || !value->GetAsBoolean(&accepted))
       NOTREACHED() << "Missing or unreadable response from dialog";
   }
 
-  delegate_->set_window(NULL);
+  delegate_->set_close_delegate(NULL);
   if (accepted)
     delegate_->Accept();
   else
     delegate_->Cancel();
 }
 
 void TabModalConfirmDialogWebUI::OnCloseContents(WebContents* source,
                                                  bool* out_close_dialog) {}
 
 bool TabModalConfirmDialogWebUI::ShouldShowDialogTitle() const {
   return true;
 }
 
 TabModalConfirmDialogWebUI::~TabModalConfirmDialogWebUI() {}
 
 void TabModalConfirmDialogWebUI::AcceptTabModalDialog() {
 }
 
 void TabModalConfirmDialogWebUI::CancelTabModalDialog() {
 }
+
+void TabModalConfirmDialogWebUI::CloseDialog() {
+  constrained_web_dialog_delegate_->OnDialogCloseFromWebUI();
+}