IDL: Support separate [MeasureAs], [DeprecateAs] counters on overloaded methods

Using [MeasureAs=*] or [DeprecateAs=*] on multiple overloads of a Blink
IDL interface method with different counter values will use the same
counter for all overloads.
This patch pushes the counting logic into the overload resolution method
so they can be distinguished.

BUG=363982

Review URL: https://codereview.chromium.org/236133017

git-svn-id: svn://svn.chromium.org/blink/trunk@173083 bbb929c8-8fbe-4397-9dbb-9b2b20218538