Change data pipe wrappers used by SerialConnection to use message pipe.

device/serial/serial_connection_unittest.cc

Index: device/serial/serial_connection_unittest.cc
diff --git a/device/serial/serial_connection_unittest.cc b/device/serial/serial_connection_unittest.cc
index 4b69158ebf95a3c3c8a8f1235b98b7ac86ed182e..a84c9e4e088bd066347e8d1678f0c5f3923968b6 100644
--- a/device/serial/serial_connection_unittest.cc
+++ b/device/serial/serial_connection_unittest.cc
@@ -269,13 +269,18 @@ TEST_F(SerialConnectionTest, Flush) {
   EXPECT_EQ(1, io_handler_->flushes());
 }
 
-TEST_F(SerialConnectionTest, Disconnect) {
+TEST_F(SerialConnectionTest, DisconnectWithSend) {
   connection_.reset();
   io_handler_->set_send_callback(base::Bind(base::DoNothing));
   ASSERT_NO_FATAL_FAILURE(Send("data"));
   WaitForEvent(EVENT_SEND_ERROR);
   EXPECT_EQ(serial::SEND_ERROR_DISCONNECTED, send_error_);
   EXPECT_EQ(0, bytes_sent_);
+  EXPECT_TRUE(io_handler_->HasOneRef());
+}
+
+TEST_F(SerialConnectionTest, DisconnectWithReceive) {
+  connection_.reset();
   ASSERT_NO_FATAL_FAILURE(Receive());
   WaitForEvent(EVENT_RECEIVE_ERROR);
   EXPECT_EQ(serial::RECEIVE_ERROR_DISCONNECTED, receive_error_);