Don't leave renderer process frozen when canceling JavaScript dialogs.

chrome/browser/ui/app_modal_dialogs/javascript_app_modal_dialog.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_APP_MODAL_DIALOGS_JAVASCRIPT_APP_MODAL_DIALOG_H_
 #define CHROME_BROWSER_UI_APP_MODAL_DIALOGS_JAVASCRIPT_APP_MODAL_DIALOG_H_
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/time/time.h"
 #include "chrome/browser/ui/app_modal_dialogs/app_modal_dialog.h"
 #include "content/public/browser/javascript_dialog_manager.h"
+#include "content/public/browser/web_contents_observer.h"
 
 // Extra data for JavaScript dialogs to add Chrome-only features.
 class ChromeJavaScriptDialogExtraData {
  public:
   ChromeJavaScriptDialogExtraData();
 
   // The time that the last JavaScript dialog was dismissed.
   base::TimeTicks last_javascript_message_dismissal_;
 
   // True if the user has decided to block future JavaScript dialogs.
   bool suppress_javascript_messages_;
 };
 
 // A controller + model class for JavaScript alert, confirm, prompt, and
 // onbeforeunload dialog boxes.
-class JavaScriptAppModalDialog : public AppModalDialog {
+class JavaScriptAppModalDialog
+    : public AppModalDialog,
+      public content::WebContentsObserver {
  public:
   typedef std::map<void*, ChromeJavaScriptDialogExtraData> ExtraDataMap;
 
   JavaScriptAppModalDialog(
       content::WebContents* web_contents,
       ExtraDataMap* extra_data_map,
       const string16& title,
       content::JavaScriptMessageType javascript_message_type,
       const string16& message_text,
       const string16& default_prompt_text,
       bool display_suppress_checkbox,
       bool is_before_unload_dialog,
       bool is_reload,
       const content::JavaScriptDialogManager::DialogClosedCallback& callback);
   virtual ~JavaScriptAppModalDialog();
 
   // Overridden from AppModalDialog:
   virtual NativeAppModalDialog* CreateNativeDialog() OVERRIDE;
   virtual bool IsJavaScriptModalDialog() OVERRIDE;
   virtual void Invalidate() OVERRIDE;
 
+  // Overridden from content::WebContentsObserver:
+  virtual void RenderViewDeleted(
+      content::RenderViewHost* render_view_host) OVERRIDE;
+
   // Callbacks from NativeDialog when the user accepts or cancels the dialog.
   void OnCancel(bool suppress_js_messages);
   void OnAccept(const string16& prompt_text, bool suppress_js_messages);
 
   // NOTE: This is only called under Views, and should be removed. Any critical
   // work should be done in OnCancel or OnAccept. See crbug.com/63732 for more.
   void OnClose();
 
   // Used only for testing. The dialog will use the given text when notifying
   // its delegate instead of whatever the UI reports.
   void SetOverridePromptText(const string16& prompt_text);
 
   // Accessors
   content::JavaScriptMessageType javascript_message_type() const {
     return javascript_message_type_;
   }
   string16 message_text() const { return message_text_; }
   string16 default_prompt_text() const { return default_prompt_text_; }
   bool display_suppress_checkbox() const { return display_suppress_checkbox_; }
   bool is_before_unload_dialog() const { return is_before_unload_dialog_; }
   bool is_reload() const { return is_reload_; }
 
  private:
   // Notifies the delegate with the result of the dialog.
   void NotifyDelegate(bool success, const string16& prompt_text,
                       bool suppress_js_messages);
 
+  // Which RenderViewHost requested the dialog and will run |callback_|.
+  content::RenderViewHost* render_view_host_;
+
   // A map of extra Chrome-only data associated with the delegate_.
   // Can be inspected via extra_data_map_[web_contents_].
   ExtraDataMap* extra_data_map_;
 
   // Information about the message box is held in the following variables.
   const content::JavaScriptMessageType javascript_message_type_;
   string16 message_text_;
   string16 default_prompt_text_;
   bool display_suppress_checkbox_;
   bool is_before_unload_dialog_;
   bool is_reload_;
 
   content::JavaScriptDialogManager::DialogClosedCallback callback_;
 
   // Used only for testing. Specifies alternative prompt text that should be
   // used when notifying the delegate, if |use_override_prompt_text_| is true.
   string16 override_prompt_text_;
   bool use_override_prompt_text_;
 
   DISALLOW_COPY_AND_ASSIGN(JavaScriptAppModalDialog);
 };
 
 #endif  // CHROME_BROWSER_UI_APP_MODAL_DIALOGS_JAVASCRIPT_APP_MODAL_DIALOG_H_