Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

chrome/renderer/searchbox/searchbox.cc

 // Copyright 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/searchbox/searchbox.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
@@ skipping 519 matching lines @@
 }
 
 void SearchBox::Reset() {
   query_.clear();
   embedded_search_request_params_ = EmbeddedSearchRequestParams();
   suggestion_ = InstantSuggestion();
   is_focused_ = false;
   is_key_capture_enabled_ = false;
   theme_info_ = ThemeBackgroundInfo();
 }
+
+void SearchBox::OnDestruct() {
+  delete this;
+}