Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

chrome/renderer/chrome_content_renderer_client.cc

 // 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.
 
 #include "chrome/renderer/chrome_content_renderer_client.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 277 matching lines @@
       : content::RenderFrameObserver(render_frame),
         continue_loading_cb_(continue_loading_cb) {}
   ~MediaLoadDeferrer() override {}
 
  private:
   // content::RenderFrameObserver implementation:
   void WasShown() override {
     continue_loading_cb_.Run();
     delete this;
   }
+  void OnDestruct() override { delete this; }
 
   const base::Closure continue_loading_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaLoadDeferrer);
 };
 
 }  // namespace
 
 ChromeContentRendererClient::ChromeContentRendererClient()
     : main_entry_time_(base::TimeTicks::Now()) {
@@ skipping 1076 matching lines @@
 // chrome.system.network.getNetworkInterfaces provides the same
 // information. Also, the enforcement of sending and binding UDP is already done
 // by chrome extension permission model.
 bool ChromeContentRendererClient::ShouldEnforceWebRTCRoutingPreferences() {
 #if defined(ENABLE_EXTENSIONS)
   return !IsStandaloneExtensionProcess();
 #else
   return true;
 #endif
 }