Returns the value for the preference with the specified |name|. Returns
NULL if the preference does not exist. The returned object contains a copy
of the underlying preference value and modifications to the returned
object will not modify the underlying preference value. This function must
be called on the browser process UI thread.
Returns the value for the preference with the specified |name|. Returns NULL if the preference does not exist. The returned object contains a copy of the underlying preference value and modifications to the returned object will not modify the underlying preference value. This function must be called on the browser process UI thread.