ozone: drm: Fix HardwareDisplayController use-after-free

ui/ozone/platform/drm/gpu/screen_manager.h

 // Copyright 2014 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 UI_OZONE_PLATFORM_DRM_GPU_SCREEN_MANAGER_H_
 #define UI_OZONE_PLATFORM_DRM_GPU_SCREEN_MANAGER_H_
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 99 matching lines @@
   // those in |mirror|. |original| is an iterator to the HDC where the
   // controller is currently present.
   bool HandleMirrorMode(HardwareDisplayControllers::iterator original,
                         HardwareDisplayControllers::iterator mirror,
                         const scoped_refptr<DrmDevice>& drm,
                         uint32_t crtc,
                         uint32_t connector);
 
   DrmWindow* FindWindowAt(const gfx::Rect& bounds) const;
 
+  void RemoveController(HardwareDisplayControllers::iterator controller);
+
   ScanoutBufferGenerator* buffer_generator_;  // Not owned.
   // List of display controllers (active and disabled).
   HardwareDisplayControllers controllers_;
 
   WidgetToWindowMap window_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenManager);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_GPU_SCREEN_MANAGER_H_