bindings: Adds non-template versions of utility functions in DOMDataStore.

http://crrev.com/478243002 needs utility functions in DOMDataStore without depending on V8T or T.
This CL introduces non-template versions of utility functions.

The suffix "NonTemplate" will be removed once we get rid of the existing template versions and remove them.

BUG=235436

Review URL: https://codereview.chromium.org/514013004

git-svn-id: svn://svn.chromium.org/blink/trunk@181038 bbb929c8-8fbe-4397-9dbb-9b2b20218538