Make a clean interface for dialog callbacks.

content/browser/javascript_dialogs.h

 // Copyright (c) 2011 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 CONTENT_BROWSER_JAVASCRIPT_DIALOG_DELEGATE_H_
 #define CONTENT_BROWSER_JAVASCRIPT_DIALOG_DELEGATE_H_
 #pragma once
 
 #include "base/string16.h"
 #include "ui/gfx/native_widget_types.h"
 
 class ExtensionHost;
 class GURL;
 class Profile;
 class TabContents;
 
 namespace IPC {
 class Message;
 }
 
 namespace content {
 
+class DialogDelegate {
+ public:
+  // Returns the root native window with which to associate the dialog.
+  virtual gfx::NativeWindow GetDialogRootWindow() = 0;
+
+  // Called right before the dialog is shown.
+  virtual void OnDialogShown() {}
+
+ protected:
+  virtual ~DialogDelegate() {}
+};
+
 // A class that invokes a JavaScript dialog must implement this interface to
 // allow the dialog implementation to get needed information and return results.
-class JavaScriptDialogDelegate {
+class JavaScriptDialogDelegate : public DialogDelegate {
  public:
   // This callback is invoked when the dialog is closed.
   virtual void OnDialogClosed(IPC::Message* reply_msg,
                               bool success,
                               const string16& user_input) = 0;
 
-  // Returns the root native window with which to associate the dialog.
-  virtual gfx::NativeWindow GetDialogRootWindow() = 0;
-
-  // Returns the TabContents implementing this delegate, or NULL if there is
-  // none. TODO(avi): This breaks encapsulation and in general sucks; figure out
-  // a better way of doing this.
-  virtual TabContents* AsTabContents() = 0;
-
-  // Returns the ExtensionHost implementing this delegate, or NULL if there is
-  // none. TODO(avi): This is even suckier than AsTabContents above as it breaks
-  // layering; figure out a better way of doing this. http://crbug.com/84604
-  virtual ExtensionHost* AsExtensionHost() = 0;
-
  protected:
   virtual ~JavaScriptDialogDelegate() {}
 };
 
-
 // An interface consisting of methods that can be called to produce JavaScript
 // dialogs.
 class JavaScriptDialogCreator {
  public:
   enum TitleType {
     DIALOG_TITLE_NONE,
     DIALOG_TITLE_PLAIN_STRING,
     DIALOG_TITLE_FORMATTED_URL
   };
 
   // Displays a JavaScript dialog. |did_suppress_message| will not be nil; if
   // |true| is returned in it, the caller will handle faking the reply.
   virtual void RunJavaScriptDialog(JavaScriptDialogDelegate* delegate,
                                    TitleType title_type,
                                    const string16& title,
                                    int dialog_flags,
                                    const string16& message_text,
                                    const string16& default_prompt_text,
                                    IPC::Message* reply_message,
                                    bool* did_suppress_message) = 0;
 
   // Displays a dialog asking the user if they want to leave a page.
   virtual void RunBeforeUnloadDialog(JavaScriptDialogDelegate* delegate,
                                      const string16& message_text,
                                      IPC::Message* reply_message) = 0;
 
-  // Resets any saved JavaScript dialog state for the delegate.
+  // Cancels all pending dialogs and resets any saved JavaScript dialog state
+  // for the delegate.
   virtual void ResetJavaScriptState(JavaScriptDialogDelegate* delegate) = 0;
 
  protected:
   virtual ~JavaScriptDialogCreator() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_JAVASCRIPT_DIALOG_DELEGATE_H_