Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

content/renderer/pepper/plugin_power_saver_helper.h

 // Copyright 2014 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 CONTENT_RENDERER_PEPPER_PLUGIN_POWER_SAVER_HELPER_H_
 #define CONTENT_RENDERER_PEPPER_PLUGIN_POWER_SAVER_HELPER_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 39 matching lines @@
   RenderFrame::PeripheralContentStatus GetPeripheralContentStatus(
       const url::Origin& main_frame_origin,
       const url::Origin& content_origin,
       const gfx::Size& unobscured_size) const;
   void WhitelistContentOrigin(const url::Origin& content_origin);
 
   // RenderFrameObserver implementation.
   void DidCommitProvisionalLoad(bool is_new_navigation,
                                 bool is_same_page_navigation) override;
   bool OnMessageReceived(const IPC::Message& message) override;
+  void OnDestruct() override;
 
   void OnUpdatePluginContentOriginWhitelist(
       const std::set<url::Origin>& origin_whitelist);
 
   // Local copy of the whitelist for the entire tab.
   std::set<url::Origin> origin_whitelist_;
 
   // Set of peripheral plugins eligible to be unthrottled ex post facto.
   std::vector<PeripheralPlugin> peripheral_plugins_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginPowerSaverHelper);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PLUGIN_POWER_SAVER_HELPER_H_