[Offline pages] Making sure that destroying the bridge does not leave notification hanging

chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.h

 // Copyright 2016 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_ANDROID_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_BRIDGE_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_BRIDGE_H_
 
 #include <stdint.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/macros.h"
-#include "base/memory/weak_ptr.h"
 #include "base/supports_user_data.h"
 #include "components/offline_pages/downloads/download_ui_adapter.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace offline_pages {
 namespace android {
 
@@ skipping 39 matching lines @@
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& j_tab);
 
   // DownloadUIAdapter::Observer implementation.
   void ItemsLoaded() override;
   void ItemAdded(const DownloadUIItem& item) override;
   void ItemUpdated(const DownloadUIItem& item) override;
   void ItemDeleted(const std::string& guid) override;
 
  private:
-  void SavePageCallback(const DownloadUIItem& item,
-                        OfflinePageModel::SavePageResult result,
-                        int64_t offline_id);
+  static void SavePageCallback(const DownloadUIItem& item,
+                               OfflinePageModel::SavePageResult result,
+                               int64_t offline_id);
 
   JavaObjectWeakGlobalRef weak_java_ref_;
   // Not owned.
   DownloadUIAdapter* download_ui_adapter_;
 
-  base::WeakPtrFactory<OfflinePageDownloadBridge> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(OfflinePageDownloadBridge);
 };
 
 }  // namespace android
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_DOWNLOADS_OFFLINE_PAGE_DOWNLOAD_BRIDGE_H_