bluetooth: Shutdown BluetoothAdapter before DBus on ChromeOS.

device/bluetooth/test/mock_bluetooth_adapter.cc

Index: device/bluetooth/test/mock_bluetooth_adapter.cc
diff --git a/device/bluetooth/test/mock_bluetooth_adapter.cc b/device/bluetooth/test/mock_bluetooth_adapter.cc
index 7c2c953f5053752049d4f2c9df1ca1d66e3b681d..8cbbb482caee62ce732f21b373a12fec24a5262f 100644
--- a/device/bluetooth/test/mock_bluetooth_adapter.cc
+++ b/device/bluetooth/test/mock_bluetooth_adapter.cc
@@ -14,6 +14,11 @@ MockBluetoothAdapter::MockBluetoothAdapter() {
 
 MockBluetoothAdapter::~MockBluetoothAdapter() {}
 
+#if defined(OS_CHROMEOS)
+void MockBluetoothAdapter::OnDBusThreadManagerShutdown() {
+}
+#endif
+
 void MockBluetoothAdapter::DeleteOnCorrectThread() const {
   delete this;
 };