isDevice(query) {
    return compare(UserAgentData.deviceName, null, query);
  }
Check if the User Agent device matches `query`.

`query` should be a string like "iPhone" or "iPad".

Valid device names include:

- Kindle
- Kindle Fire
- Unknown
- iPad
- iPhone
- iPod
- etc...

An authoritative list can be found in the PHP `DeviceDetector` class and
related classes in the same file (see calls to `new UserAgentDevice` here:
https://fburl.com/50728332).

@note Function results are memoized

@param {string} query Query of the form "Name"
@return {boolean}