Move Window use counters from DOMWindow.cpp to Window.idl where possible

None of these are used internally, but even if they were it's better to
measure at the bindings level to only measure Web-exposed usage.

BUG=none

Review URL: https://codereview.chromium.org/251043007

git-svn-id: svn://svn.chromium.org/blink/trunk@172900 bbb929c8-8fbe-4397-9dbb-9b2b20218538