[Ozone-Drm] Revert of holding on to the DRM FDs in the browser process

ui/ozone/platform/drm/host/drm_display_host_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_HOST_DRM_DISPLAY_HOST_MANAGER_H_
 #define UI_OZONE_PLATFORM_DRM_HOST_DRM_DISPLAY_HOST_MANAGER_H_
 
 #include <map>
 #include <queue>
+#include <set>
 
-#include "base/containers/scoped_ptr_hash_map.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/display/types/native_display_delegate.h"
 #include "ui/events/ozone/device/device_event.h"
 #include "ui/events/ozone/device/device_event_observer.h"
 #include "ui/ozone/public/gpu_platform_support_host.h"
 
@@ skipping 103 matching lines @@
   // Used to serialize display event processing. This is done since
   // opening/closing DRM devices cannot be done on the UI thread and are handled
   // on a worker thread. Thus, we need to queue events in order to process them
   // in the correct order.
   std::queue<DisplayEvent> event_queue_;
 
   // True if a display event is currently being processed on a worker thread.
   bool task_pending_;
 
   // Keeps track of all the active DRM devices.
-  base::ScopedPtrHashMap<base::FilePath, scoped_ptr<DrmDeviceHandle>>
-      drm_devices_;
+  std::set<base::FilePath> drm_devices_;
+
+  // This is used to cache the primary DRM device until the channel is
+  // established.
+  scoped_ptr<DrmDeviceHandle> primary_drm_device_handle_;
 
   base::WeakPtrFactory<DrmDisplayHostManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DrmDisplayHostManager);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRM_HOST_DRM_DISPLAY_HOST_MANAGER_H_