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

chrome/browser/ui/gtk/login_prompt_gtk.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/login/login_prompt.h"
 
 #include <gtk/gtk.h>
 
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
@@ skipping 23 matching lines @@
 // the UI thread) to the net::URLRequest (on the I/O thread).
 // This class uses ref counting to ensure that it lives until all InvokeLaters
 // have been called.
 class LoginHandlerGtk : public LoginHandler,
                         public ConstrainedWindowGtkDelegate {
  public:
   LoginHandlerGtk(net::AuthChallengeInfo* auth_info, net::URLRequest* request)
       : LoginHandler(auth_info, request),
         username_entry_(NULL),
         password_entry_(NULL),
-        ok_(NULL) {
+        ok_(NULL),
+        dialog_(NULL) {
   }
 
   // LoginModelObserver implementation.
   virtual void OnAutofillDataAvailable(const string16& username,
                                        const string16& password) OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
     // NOTE: Would be nice to use gtk_entry_get_text_length, but it is fairly
     // new and not always in our GTK version.
     if (strlen(gtk_entry_get_text(GTK_ENTRY(username_entry_))) == 0) {
@@ skipping 51 matching lines @@
     SetModel(manager);
 
     // Scary thread safety note: This can potentially be called *after* SetAuth
     // or CancelAuth (say, if the request was cancelled before the UI thread got
     // control).  However, that's OK since any UI interaction in those functions
     // will occur via an InvokeLater on the UI thread, which is guaranteed
     // to happen after this is called (since this was InvokeLater'd first).
     WebContents* requesting_contents = GetWebContentsForLogin();
     DCHECK(requesting_contents);
 
-    SetDialog(new ConstrainedWindowGtk(requesting_contents, this));
+    dialog_ = new ConstrainedWindowGtk(requesting_contents, this);
     NotifyAuthNeeded();
   }
 
+  virtual void CloseDialog() OVERRIDE {
+    // The hosting WebContentsModalDialog may have been freed.
+    if (dialog_)
+      dialog_->CloseWebContentsModalDialog();
+  }
+
   // Overridden from ConstrainedWindowGtkDelegate:
   virtual GtkWidget* GetWidgetRoot() OVERRIDE {
     return root_.get();
   }
 
   virtual GtkWidget* GetFocusWidget() OVERRIDE {
     return username_entry_;
   }
 
   virtual void DeleteDelegate() OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
     // The constrained window is going to delete itself; clear our pointer.
-    SetDialog(NULL);
+    dialog_ = NULL;
     SetModel(NULL);
 
     ReleaseSoon();
   }
 
  protected:
   virtual ~LoginHandlerGtk() {
     root_.Destroy();
   }
 
  private:
   friend class LoginPrompt;
 
   CHROMEGTK_CALLBACK_0(LoginHandlerGtk, void, OnOKClicked);
   CHROMEGTK_CALLBACK_0(LoginHandlerGtk, void, OnCancelClicked);
   CHROMEGTK_CALLBACK_1(LoginHandlerGtk, void, OnPromptHierarchyChanged,
                        GtkWidget*);
 
   // The GtkWidgets that form our visual hierarchy:
   // The root container we pass to our parent.
   ui::OwnedWidgetGtk root_;
 
   // GtkEntry widgets that the user types into.
   GtkWidget* username_entry_;
   GtkWidget* password_entry_;
   GtkWidget* ok_;
 
+  ConstrainedWindowGtk* dialog_;
+
   DISALLOW_COPY_AND_ASSIGN(LoginHandlerGtk);
 };
 
 void LoginHandlerGtk::OnOKClicked(GtkWidget* sender) {
   SetAuth(
       UTF8ToUTF16(gtk_entry_get_text(GTK_ENTRY(username_entry_))),
       UTF8ToUTF16(gtk_entry_get_text(GTK_ENTRY(password_entry_))));
 }
 
 void LoginHandlerGtk::OnCancelClicked(GtkWidget* sender) {
@@ skipping 11 matching lines @@
   // button the default action and mess with the focus.
   gtk_widget_set_can_default(ok_, TRUE);
   gtk_widget_grab_default(ok_);
 }
 
 // static
 LoginHandler* LoginHandler::Create(net::AuthChallengeInfo* auth_info,
                                    net::URLRequest* request) {
   return new LoginHandlerGtk(auth_info, request);
 }