GTTF: Add missing virtual destructors.

chrome/browser/ui/panels/display_settings_provider.h

 // Copyright (c) 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_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_
 #define CHROME_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_
 
 #include "base/observer_list.h"
 #include "base/timer.h"
 #include "ui/gfx/rect.h"
@@ skipping 14 matching lines @@
 
   // Indicates current visibility state of the desktop bar.
   enum DesktopBarVisibility {
     DESKTOP_BAR_VISIBLE,
     DESKTOP_BAR_ANIMATING,
     DESKTOP_BAR_HIDDEN
   };
 
   class DisplayAreaObserver {
    public:
+    virtual ~DisplayAreaObserver() { }
+
     virtual void OnDisplayAreaChanged(const gfx::Rect& display_area) = 0;
   };
 
   class DesktopBarObserver {
    public:
+    virtual ~DesktopBarObserver() { }
+
     virtual void OnAutoHidingDesktopBarVisibilityChanged(
         DesktopBarAlignment alignment, DesktopBarVisibility visibility) = 0;
   };
 
   class FullScreenObserver {
    public:
+    virtual ~FullScreenObserver() { }
+
     virtual void OnFullScreenModeChanged(bool is_full_screen) = 0;
   };
 
   static DisplaySettingsProvider* Create();
 
   virtual ~DisplaySettingsProvider();
 
   // Subscribes/unsubscribes from the display settings change notification.
   void AddDisplayAreaObserver(DisplayAreaObserver* observer);
   void RemoveDisplayAreaObserver(DisplayAreaObserver* observer);
@@ skipping 101 matching lines @@
   // True if full screen mode or presentation mode is entered.
   bool is_full_screen_;
 
   // Timer used to detect full-screen mode change.
   base::RepeatingTimer<DisplaySettingsProvider> full_screen_mode_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplaySettingsProvider);
 };
 
 #endif  // CHROME_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_