Invalidate the page state when restoring WebUIs

This CL invalidates the serialized page state any chrome:// URLs,
causing the page to get reloaded rather than restored. This will prevent
the upgrade to MD History from breaking things since it lives at a
different physical URL than classic history.

BUG=614758
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2355543003
Cr-Commit-Position: refs/heads/master@{#420600}
6 files changed