Pulls in the remainding security updates from the first Chrome 55 release.

Changes:
    f0e73b6d Add mus and catapult project files
    804dc2f Merge remote-tracking branch 'origin/upstream-master' into 53-based
    461b9af [Backport] Merge: "INPUT element: Do not dispatch events in detachLayoutTree()." to M55 branch.
    0119f04 [Backport] Disallow frame swap during frame detach.
    7aab930 [Backport] Do not call an event listener on a cloned node in svg <use>'s UA shadow tree
    e9660fc [Backport] Do not re-create the page view when accessing from Document::removeField.
    2ff5d16 [Backport] Merge to 2883 "[DevTools] Move sanitize url to devtools_ui.cc."
    482005e [Backport] Null CPDF_CountedObj::m_pObj prior to deletion
    ba38b74 [Backport] [inspector] added check that context always survives inspected context
    02ac973 [Backport] Don't send loading completion callbacks for detaching frames.
    803a9bb [Backport] Merged: Avoid using stale InspectedContext pointers
    b6888f2...