Removing file_thread_task_runner parameter from SerialIoHandler

device/serial/test_serial_io_handler.cc

Index: device/serial/test_serial_io_handler.cc
diff --git a/device/serial/test_serial_io_handler.cc b/device/serial/test_serial_io_handler.cc
index d0b4ee6704e30accd639604c76eba1a79c66f4cf..50c38dbc5eee5a817a6747f5bb7ef220a74f5aa5 100644
--- a/device/serial/test_serial_io_handler.cc
+++ b/device/serial/test_serial_io_handler.cc
@@ -15,12 +15,11 @@
 namespace device {
 
 TestSerialIoHandler::TestSerialIoHandler()
-    : SerialIoHandler(NULL, NULL),
+    : SerialIoHandler(NULL),
       opened_(false),
       dtr_(false),
       rts_(false),
-      flushes_(0) {
-}
+      flushes_(0) {}
 
 scoped_refptr<SerialIoHandler> TestSerialIoHandler::Create() {
   return scoped_refptr<SerialIoHandler>(new TestSerialIoHandler);