Add use counters for a number of extensions and non-standard APIs

Found by searching for "extension" and "non-standard" in *.idl.

Some APIs which are documented as extension/non-standard in the IDL are
now standardized, and no counters were added for those, like
Document.readyState.

Ad-hoc testing was done in Firefox and IE. It looks like the comments
about IE/Mozilla/WebKit extensions are mostly accurate, and none of the
touched APIs are implemented in both Firefox and IE.

BUG=none

Review URL: https://codereview.chromium.org/268663005

git-svn-id: svn://svn.chromium.org/blink/trunk@173180 bbb929c8-8fbe-4397-9dbb-9b2b20218538