Fix typos in device/bluetooth headers.

device/bluetooth/bluetooth_init_win.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef DEVICE_BLUETOOTH_BLUETOOTH_INIT_WIN_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_INIT_WIN_H_
 
 // windows.h needs to be included before BluetoothAPIs.h.
 #include <windows.h>
 
 #include <BluetoothAPIs.h>
 #if defined(_WIN32_WINNT_WIN8) && _MSC_VER < 1700
 // The Windows 8 SDK defines FACILITY_VISUALCPP in winerror.h.
 #undef FACILITY_VISUALCPP
 #endif
 #include <delayimp.h>
 #include <ws2def.h>
 #include <ws2bth.h>
 
 #pragma comment(lib, "Bthprops.lib")
 #pragma comment(lib, "BluetoothApis.lib")
 
 namespace device {
 namespace bluetooth_init_win {
 
 // Returns true if the machine has a bluetooth stack available. The first call
 // to this function will involve file IO, so it should be done on an appropriate
-// thread. This function is not threadsafe.
+// thread. This function is not thread-safe.
 bool HasBluetoothStack();
 
 }  // namespace bluetooth_init_win
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_INIT_WIN_H_