Remove unused include in sequenced_worker_pool.h

media/base/android/media_drm_bridge.h

 // Copyright (c) 2013 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 MEDIA_BASE_ANDROID_MEDIA_DRM_BRIDGE_H_
 #define MEDIA_BASE_ANDROID_MEDIA_DRM_BRIDGE_H_
 
 #include <jni.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "media/base/android/media_drm_bridge_cdm_context.h"
 #include "media/base/android/provision_fetcher.h"
 #include "media/base/cdm_promise.h"
 #include "media/base/cdm_promise_adapter.h"
 #include "media/base/media_export.h"
 #include "media/base/media_keys.h"
 #include "media/base/player_tracker.h"
 #include "media/cdm/player_tracker_impl.h"
 #include "url/gurl.h"
 
 class GURL;
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace media {
 
 // Implements a CDM using Android MediaDrm API.
 //
 // Thread Safety:
 //
 // This class lives on the thread where it is created. All methods must be
 // called on the |task_runner_| except for the PlayerTracker methods and
 // SetMediaCryptoReadyCB(), which can be called on any thread.
 
@@ skipping 272 matching lines @@
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<MediaDrmBridge> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaDrmBridge);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_ANDROID_MEDIA_DRM_BRIDGE_H_