Rename DOMApplicationCache to ApplicationCache and expose it to JS

Rename DOMApplicationCache to ApplicationCache and expose it to JavaScript
as per the latest specification:
http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#applicationcache

This is particularly useful as ApplicationCache exposes constant values.
IE10 already exposes ApplicationCache to JavaScript while Firefox 23 does
not.

BUG=275669
R=tkent@chromium.org

Review URL: https://codereview.chromium.org/22802012

git-svn-id: svn://svn.chromium.org/blink/trunk@156391 bbb929c8-8fbe-4397-9dbb-9b2b20218538