Remove DeviceMonitorLinux::WillDestroyCurrentMessageLoop().

device/hid/mock_hid_service.cc

Index: device/hid/mock_hid_service.cc
diff --git a/device/hid/mock_hid_service.cc b/device/hid/mock_hid_service.cc
index 7c73a3543c8f32a5480f79b588990ee593dbae29..3b913cf696d044b8fa5d8c6a5c5904393cedcf26 100644
--- a/device/hid/mock_hid_service.cc
+++ b/device/hid/mock_hid_service.cc
@@ -8,7 +8,10 @@ namespace device {
 
 MockHidService::MockHidService() {}
 
-MockHidService::~MockHidService() {}
+MockHidService::~MockHidService() {
+  // Shutdown() must be called before the base class destructor.
+  Shutdown();
+}
 
 void MockHidService::AddDevice(scoped_refptr<HidDeviceInfo> info) {
   HidService::AddDevice(info);