Remove unused include in sequenced_worker_pool.h

device/usb/usb_service.h

Index: device/usb/usb_service.h
diff --git a/device/usb/usb_service.h b/device/usb/usb_service.h
index b3949a77aaaac838c8e64fb1ce54377f341b04ec..85a3922461ccaf5af507a81fb2053d4f9511d94f 100644
--- a/device/usb/usb_service.h
+++ b/device/usb/usb_service.h
@@ -15,12 +15,10 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
+#include "base/sequenced_task_runner.h"
+#include "base/single_thread_task_runner.h"
 #include "base/threading/non_thread_safe.h"
 
-namespace base {
-class SequencedTaskRunner;
-}
-
 namespace device {
 
 class UsbDevice;