Revert 153571 - Create base class for TabHelpers.

chrome/browser/tab_contents/web_contents_user_data.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_TAB_CONTENTS_WEB_CONTENTS_USER_DATA_H_
-#define CHROME_BROWSER_TAB_CONTENTS_WEB_CONTENTS_USER_DATA_H_
-
-#include "base/supports_user_data.h"
-#include "content/public/browser/web_contents.h"
-
-// A base class for classes attached to, and scoped to, the lifetime of a
-// WebContents. For example:
-//
-// class FooTabHelper : public WebContentsUserData<FooTabHelper> {
-//  public:
-//   explicit FooTabHelper(content::WebContents* contents);
-//   virtual ~FooTabHelper();
-//
-template <typename T>
-class WebContentsUserData : public base::SupportsUserData::Data {
- public:
-  // Creates an object of type T, and attaches it to the specified WebContents.
-  static void CreateForWebContents(content::WebContents* contents) {
-    void* key = reinterpret_cast<void*>(&CreateForWebContents);
-    contents->SetUserData(key, new T(contents));
-  }
-
-  // Retrieves the instance of type T that was attached to the specified
-  // WebContents (via CreateForWebContents above) and returns it. If no instance
-  // of the type was attached, returns NULL.
-  static T* FromWebContents(content::WebContents* contents) {
-    void* key = reinterpret_cast<void*>(&CreateForWebContents);
-    return static_cast<T*>(contents->GetUserData(key));
-  }
-};
-
-#endif  // CHROME_BROWSER_TAB_CONTENTS_WEB_CONTENTS_USER_DATA_H_