Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

content/renderer/push_messaging/push_messaging_dispatcher.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_PUSH_MESSAGING_PUSH_MESSAGING_DISPATCHER_H_
 #define CONTENT_RENDERER_PUSH_MESSAGING_PUSH_MESSAGING_DISPATCHER_H_
 
 #include <stdint.h>
 #include <string>
 #include <vector>
@@ skipping 21 matching lines @@
 struct ManifestDebugInfo;
 struct PushSubscriptionOptions;
 
 class PushMessagingDispatcher : public RenderFrameObserver,
                                 public blink::WebPushClient {
  public:
   explicit PushMessagingDispatcher(RenderFrame* render_frame);
   ~PushMessagingDispatcher() override;
 
  private:
-  // RenderFrame::Observer implementation.
+  // RenderFrameObserver implementation.
   bool OnMessageReceived(const IPC::Message& message) override;
+  void OnDestruct() override;
 
   // WebPushClient implementation.
   void subscribe(
       blink::WebServiceWorkerRegistration* service_worker_registration,
       const blink::WebPushSubscriptionOptions& options,
       blink::WebPushSubscriptionCallbacks* callbacks) override;
 
   void DidGetManifest(
       blink::WebServiceWorkerRegistration* service_worker_registration,
       const blink::WebPushSubscriptionOptions& options,
@@ skipping 16 matching lines @@
 
   IDMap<blink::WebPushSubscriptionCallbacks, IDMapOwnPointer>
       subscription_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(PushMessagingDispatcher);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PUSH_MESSAGING_PUSH_MESSAGING_DISPATCHER_H_