Measure usage for Text.prototype.replaceWholeText()

Measure usage for Text.prototype.replaceWholeText() as it was removed
from DOM4:
http://www.w3.org/TR/2012/WD-dom-20121206/#text

This will allow us to determine if it can be deprecated / removed or
whether DOM4 needs to add it back.

Note that Firefox has already dropped support for this method. However,
IE10 still supports it.

R=arv
BUG=267521

Review URL: https://chromiumcodereview.appspot.com/22182002

git-svn-id: svn://svn.chromium.org/blink/trunk@155617 bbb929c8-8fbe-4397-9dbb-9b2b20218538