Switch SearchEngineTabHelper to use WebContentsUserData.

chrome/browser/ui/search_engines/search_engine_tab_helper.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 CHROME_BROWSER_UI_SEARCH_ENGINES_SEARCH_ENGINE_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_SEARCH_ENGINES_SEARCH_ENGINE_TAB_HELPER_H_
 
+#include "chrome/browser/tab_contents/web_contents_user_data.h"
 #include "chrome/browser/ui/find_bar/find_bar_controller.h"
 #include "chrome/browser/ui/find_bar/find_notification_details.h"
 #include "chrome/common/search_provider.h"
 #include "content/public/browser/web_contents_observer.h"
 
 class SearchEngineTabHelperDelegate;
 
 // Per-tab search engine manager. Handles dealing search engine processing
 // functionality.
-class SearchEngineTabHelper : public content::WebContentsObserver {
+class SearchEngineTabHelper
+    : public content::WebContentsObserver,
+      public WebContentsUserData<SearchEngineTabHelper> {
  public:
-  explicit SearchEngineTabHelper(content::WebContents* web_contents);
   virtual ~SearchEngineTabHelper();
 
   SearchEngineTabHelperDelegate* delegate() const { return delegate_; }
   void set_delegate(SearchEngineTabHelperDelegate* d) { delegate_ = d; }
 
   // content::WebContentsObserver overrides.
   virtual void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
  private:
+  explicit SearchEngineTabHelper(content::WebContents* web_contents);
+  static int kUserDataKey;
+  friend class WebContentsUserData<SearchEngineTabHelper>;
+
   // Handles when a page specifies an OSDD (OpenSearch Description Document).
   void OnPageHasOSDD(int32 page_id,
                      const GURL& doc_url,
                      const search_provider::OSDDType& msg_provider_type);
 
   // If params has a searchable form, this tries to create a new keyword.
   void GenerateKeywordIfNecessary(
       const content::FrameNavigateParams& params);
 
   // Delegate for notifying our owner about stuff. Not owned by us.
   SearchEngineTabHelperDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchEngineTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_SEARCH_ENGINES_SEARCH_ENGINE_TAB_HELPER_H_