bindings: Moves calls to refObject() into associateObjectWithWrapperNonTemplate.

associateObjectWithWrapperNonTemplate makes the given wrapper reference to
the given object, so it's natural that associateObjectWithWrapperNonTemplate
is responsible to count up the reference counter of the given object.

BUG=235436

Review URL: https://codereview.chromium.org/590153002

git-svn-id: svn://svn.chromium.org/blink/trunk@182416 bbb929c8-8fbe-4397-9dbb-9b2b20218538