Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

chrome/renderer/searchbox/searchbox.h

 // 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.
 
 #ifndef CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_
 #define CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 122 matching lines @@
   bool is_focused() const { return is_focused_; }
   bool is_input_in_progress() const { return is_input_in_progress_; }
   bool is_key_capture_enabled() const { return is_key_capture_enabled_; }
   bool display_instant_results() const { return display_instant_results_; }
   const base::string16& query() const { return query_; }
   const InstantSuggestion& suggestion() const { return suggestion_; }
 
  private:
   // Overridden from content::RenderViewObserver:
   bool OnMessageReceived(const IPC::Message& message) override;
+  void OnDestruct() override;
 
   void OnSetPageSequenceNumber(int page_seq_no);
   void OnChromeIdentityCheckResult(const base::string16& identity,
                                    bool identity_match);
   void OnDetermineIfPageSupportsInstant();
   void OnFocusChanged(OmniboxFocusState new_focus_state,
                       OmniboxFocusChangeReason reason);
   void OnHistorySyncCheckResult(bool sync_history);
   void OnMostVisitedChanged(
       const std::vector<InstantMostVisitedItem>& items);
@@ skipping 23 matching lines @@
   InstantRestrictedIDCache<InstantMostVisitedItem> most_visited_items_cache_;
   ThemeBackgroundInfo theme_info_;
   base::string16 query_;
   EmbeddedSearchRequestParams embedded_search_request_params_;
   InstantSuggestion suggestion_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchBox);
 };
 
 #endif  // CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_