Revert of [Ozone-GBM] Handle GPU crashes

ui/ozone/platform/dri/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_DRI_SCREEN_MANAGER_H_
 #define UI_OZONE_PLATFORM_DRI_SCREEN_MANAGER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 11 matching lines @@
 
 class DriWrapper;
 class ScanoutBufferGenerator;
 
 // Responsible for keeping track of active displays and configuring them.
 class ScreenManager {
  public:
   ScreenManager(DriWrapper* dri, ScanoutBufferGenerator* surface_generator);
   virtual ~ScreenManager();
 
-  // Register a display controller. This must be called before trying to
-  // configure it.
-  void AddDisplayController(uint32_t crtc, uint32_t connector);
-
   // Remove a display controller from the list of active controllers. The
   // controller is removed since it was disconnected.
   void RemoveDisplayController(uint32_t crtc);
 
-  // Configure a display controller. The display controller is identified by
-  // (|crtc|, |connector|) and the controller is modeset using |mode|.
+  // Configure (and add if not present) a display controller. The display
+  // controller is identified by (|crtc|, |connector|) and the controller is
+  // modeset using |mode|.
   bool ConfigureDisplayController(uint32_t crtc,
                                   uint32_t connector,
                                   const gfx::Point& origin,
                                   const drmModeModeInfo& mode);
 
   // Disable the display controller identified by |crtc|. Note, the controller
   // may still be connected, so this does not remove the controller.
   bool DisableDisplayController(uint32_t crtc);
 
   // Returns a reference to the display controller configured to display within
@@ skipping 39 matching lines @@
   ScanoutBufferGenerator* buffer_generator_;  // Not owned.
   // List of display controllers (active and disabled).
   HardwareDisplayControllers controllers_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenManager);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_SCREEN_MANAGER_H_