IDL: Support [DeprecateAs] and [MeasureAs] on constants

For constants with [DeprecateAs] or [MeasureAs], create the property
using v8::Template::SetNativeDataProperty() instead, using a simple
accessor callback function that handles the deprecation/measuring and
returns the constant value.

BUG=358506

Review URL: https://codereview.chromium.org/577303002

git-svn-id: svn://svn.chromium.org/blink/trunk@182492 bbb929c8-8fbe-4397-9dbb-9b2b20218538