DevTools: Implement undo, redo operations for the DOMStorage views.

R=apavlov, pfeldman

Review URL: https://chromiumcodereview.appspot.com/21163003

git-svn-id: svn://svn.chromium.org/blink/trunk@155573 bbb929c8-8fbe-4397-9dbb-9b2b20218538