Remove unused include in sequenced_worker_pool.h

media/base/android/media_drm_bridge.h

Index: media/base/android/media_drm_bridge.h
diff --git a/media/base/android/media_drm_bridge.h b/media/base/android/media_drm_bridge.h
index 1a6d882b205972cf0a983de460d8cf9b87ea407e..080f7fa396ce0030107a31cdcdc2a8c3defc2114 100644
--- a/media/base/android/media_drm_bridge.h
+++ b/media/base/android/media_drm_bridge.h
@@ -15,6 +15,7 @@
 #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"
@@ -28,6 +29,10 @@
 
 class GURL;
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace media {
 
 // Implements a CDM using Android MediaDrm API.