Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

content/renderer/media/renderer_webmediaplayer_delegate.h

 // Copyright 2015 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_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_
 #define CONTENT_RENDERER_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 35 matching lines @@
                bool is_remote,
                base::TimeDelta duration) override;
   void DidPause(int delegate_id, bool reached_end_of_stream) override;
   void PlayerGone(int delegate_id) override;
   bool IsHidden() override;
 
   // content::RenderFrameObserver overrides.
   void WasHidden() override;
   void WasShown() override;
   bool OnMessageReceived(const IPC::Message& msg) override;
+  void OnDestruct() override;
 
   // Zeros out |idle_cleanup_interval_|, and sets |idle_timeout_| to
   // |idle_timeout|. A zero cleanup interval will cause the idle timer to run
   // with each run of the message loop.
   void SetIdleCleanupParamsForTesting(base::TimeDelta idle_timeout,
                                       base::TickClock* tick_clock);
   bool IsIdleCleanupTimerRunningForTesting() const {
     return idle_cleanup_timer_.IsRunning();
   }
 
@@ skipping 33 matching lines @@
   // for testing.
   std::unique_ptr<base::DefaultTickClock> default_tick_clock_;
   base::TickClock* tick_clock_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererWebMediaPlayerDelegate);
 };
 
 }  // namespace media
 
 #endif  // CONTENT_RENDERER_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_