MV iframes: Change local NTP to render most visited using iframes.

This depends on all the other parts split out from CL 14578005.

BUG=228940
R=jhawkins@chromium.org, palmer@chromium.org, samarth@chromium.org

Review URL: https://codereview.chromium.org/14769012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198463 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed