Clean up HID backend and API.

device/hid/hid_utils_mac.h

 // Copyright (c) 2014 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_HID_HID_UTILS_MAC_H_
 #define DEVICE_HID_HID_UTILS_MAC_H_
 
 #include "base/callback.h"

[Mark Mentovai, 2014/02/13 22:37:51]

Both of these #includes are unused.

[Ken Rockot(use gerrit already), 2014/02/18 19:43:09]

Done.

 #include "base/memory/ref_counted.h"
 
 #include <IOKit/hid/IOHIDManager.h>

[Mark Mentovai, 2014/02/13 22:37:51]

You also need <CoreFoundation/CoreFoundation.h>, <string>, and something that
guarantees you get int32_t, either "base/basictypes.h" or <stdint.h>.

Once you put those #includes in this file, you won’t need to also list them in
the .cc.

[Ken Rockot(use gerrit already), 2014/02/18 19:43:09]

Done.

 
 namespace device {
 
-bool GetHidIntProperty(IOHIDDeviceRef device, CFStringRef key, int32_t* result);
+int32_t GetHidIntProperty(IOHIDDeviceRef device, CFStringRef key);
 
-bool GetHidStringProperty(IOHIDDeviceRef device,
-                       CFStringRef key,
-                       std::string* result);
+std::string GetHidStringProperty(IOHIDDeviceRef device, CFStringRef key);
+
+bool TryGetHidIntProperty(IOHIDDeviceRef device,
+                          CFStringRef key,
+                          int32_t* result);
+
+bool TryGetHidStringProperty(IOHIDDeviceRef device,
+                             CFStringRef key,
+                             std::string* result);
 
 }  // namespace device
 
 #endif  // DEVICE_HID_HID_UTILS_MAC_H_