Remove code to support Objective-C bindings

      Several bits of core have extra method overloads or even separate methods
that existed only to support WebKit's objc bindings.
There's no need for this code to exist in Blink.

Review URL: https://chromiumcodereview.appspot.com/13844022

git-svn-id: svn://svn.chromium.org/blink/trunk@149373 bbb929c8-8fbe-4397-9dbb-9b2b20218538