Drop UseCounters for certain properties on CSSStyleDeclaration

Blink/WebKit/IE supports properties on CSSStyleDeclaration that are
the literal names of the CSS properties, for instance
style['font-face']. We have two related counters for measuring how
often this capability is used.

The consensus on bug 290055 is that we can't drop the corresponding
functionality because of high usage both on the counters and in
libraries. Instead drop the counters since they have played their
part.

R=ojan
BUG=290055

Review URL: https://codereview.chromium.org/190663013

git-svn-id: svn://svn.chromium.org/blink/trunk@168930 bbb929c8-8fbe-4397-9dbb-9b2b20218538