Switch PluginObserver to use WebContentsUserData.

chrome/browser/ui/tab_contents/tab_contents.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_TAB_CONTENTS_TAB_CONTENTS_H_
 #define CHROME_BROWSER_UI_TAB_CONTENTS_TAB_CONTENTS_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
@@ skipping 24 matching lines @@
 class HungPluginTabHelper;
 class InfoBarControllerContentsCreator;
 class InfoBarTabHelper;
 class InstantLoader;
 class NavigationMetricsRecorder;
 class OffscreenTabContentsCreator;
 class PanelHost;
 class PasswordManager;
 class PasswordManagerDelegate;
 class PepperBrokerObserver;
-class PluginObserver;
 class PrefsTabHelper;
 class Profile;
 class SearchEngineTabHelper;
 class ShellWindow;
 class TabAutofillManagerDelegate;
 class TabContentsTestHarness;
 class TabSpecificContentSettings;
 class TabStripModel;
 class TabStripModelContentsCreator;
 class ThumbnailGenerator;
@@ skipping 232 matching lines @@
   scoped_ptr<ZoomController> zoom_controller_;
 
   // Per-tab observers ---------------------------------------------------------
   // (These provide no API for callers; objects that need to exist 1:1 with tabs
   // and silently do their thing live here.)
 
   scoped_ptr<extensions::WebNavigationTabObserver> webnavigation_observer_;
   scoped_ptr<ExternalProtocolObserver> external_protocol_observer_;
   scoped_ptr<NavigationMetricsRecorder> navigation_metrics_recorder_;
   scoped_ptr<PepperBrokerObserver> pepper_broker_observer_;
-  scoped_ptr<PluginObserver> plugin_observer_;
   scoped_ptr<safe_browsing::SafeBrowsingTabObserver>
       safe_browsing_tab_observer_;
 
   // WebContents (MUST BE LAST) ------------------------------------------------
 
   // If true, we're running the destructor.
   bool in_destructor_;
 
   // The supporting objects need to outlive the WebContents dtor (as they may
   // be called upon during its execution). As a result, this must come last
   // in the list.
   scoped_ptr<content::WebContents> web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CHROME_BROWSER_UI_TAB_CONTENTS_TAB_CONTENTS_H_