Add a preference to clear plugin data on browser shutdown.

chrome/browser/plugin_data_remover_helper.h

+// Copyright (c) 2010 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_PLUGIN_DATA_REMOVER_HELPER_H_
+#define CHROME_BROWSER_PLUGIN_DATA_REMOVER_HELPER_H_
+#pragma once
+
+#include "base/ref_counted.h"
+#include "chrome/browser/prefs/pref_member.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/common/notification_registrar.h"
+
+class Profile;
+
+// Helper class modeled after BooleanPrefMember to (asynchronously) update
+// the preference specifying whether clearing plug-in data is supported
+// by an installed plug-in.
+// It should only be used from the UI thread. The client has to make sure that
+// the passed PrefService outlives this object.
+class PluginDataRemoverHelper : public NotificationObserver {
+ public:
+  PluginDataRemoverHelper();
+  ~PluginDataRemoverHelper();
+
+  // Binds this object to the |pref_name| preference in |prefs|, notifying
+  // |observer| if the value changes.
+  // This fires off a request to the NPAPI::PluginList (via PluginDataRemover)
+  // on the FILE thread to get the list of installed plug-ins.
+  void Init(const char* pref_name,
+            PrefService* prefs,
+            NotificationObserver* observer);
+
+  bool GetValue() const { return pref_.GetValue(); }
+
+  // NotificationObserver methods:
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+ private:
+  class Internal;
+
+  BooleanPrefMember pref_;
+  NotificationRegistrar registrar_;
+  scoped_refptr<Internal> internal_;
+
+  DISALLOW_COPY_AND_ASSIGN(PluginDataRemoverHelper);
+};
+
+#endif  // CHROME_BROWSER_PLUGIN_DATA_REMOVER_HELPER_H_