Manage HidService lifetime in DeviceClient implementations.

device/hid/hid_service_mac.cc

Index: device/hid/hid_service_mac.cc
diff --git a/device/hid/hid_service_mac.cc b/device/hid/hid_service_mac.cc
index 081e66876b99aee49c561d8fb1f284dd3435f187..babb91f348d0cd88d46fb20b66aace3fb7571fce 100644
--- a/device/hid/hid_service_mac.cc
+++ b/device/hid/hid_service_mac.cc
@@ -129,6 +129,8 @@ HidServiceMac::HidServiceMac(
   FirstEnumerationComplete();
 }
 
+HidServiceMac::~HidServiceMac() {}
+
 void HidServiceMac::Connect(const HidDeviceId& device_id,
                             const ConnectCallback& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ -180,9 +182,6 @@ void HidServiceMac::Connect(const HidDeviceId& device_id,
                                           file_task_runner_))));
 }
 
-HidServiceMac::~HidServiceMac() {
-}
-
 // static
 void HidServiceMac::FirstMatchCallback(void* context, io_iterator_t iterator) {
   DCHECK_EQ(CFRunLoopGetMain(), CFRunLoopGetCurrent());