Virtual destructors should have virtual keyword.

chrome/browser/renderer_host/render_widget_host_view_gtk.h

 // Copyright (c) 2011 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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #pragma once
 
 #include <gdk/gdk.h>
 
@@ skipping 29 matching lines @@
 typedef struct _GtkClipboard GtkClipboard;
 typedef struct _GtkSelectionData GtkSelectionData;
 
 // -----------------------------------------------------------------------------
 // See comments in render_widget_host_view.h about this class and its members.
 // -----------------------------------------------------------------------------
 class RenderWidgetHostViewGtk : public RenderWidgetHostView,
                                 public ui::AnimationDelegate {
  public:
   explicit RenderWidgetHostViewGtk(RenderWidgetHost* widget);
-  ~RenderWidgetHostViewGtk();
+  virtual ~RenderWidgetHostViewGtk();
 
   // Initialize this object for use as a drawing area.
   void InitAsChild();
 
   // RenderWidgetHostView implementation.
   virtual void InitAsPopup(RenderWidgetHostView* parent_host_view,
                            const gfx::Rect& pos);
   virtual void InitAsFullscreen();
   virtual RenderWidgetHost* GetRenderWidgetHost() const;
   virtual void DidBecomeSelected();
@@ skipping 193 matching lines @@
   // menus and drags.
   GdkEventButton* last_mouse_down_;
 
 #if defined(OS_CHROMEOS)
   // Custimized tooltip window.
   scoped_ptr<views::TooltipWindowGtk> tooltip_window_;
 #endif  // defined(OS_CHROMEOS)
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_