Navigation transitions: Hide transition elements by setting opacity: 0 rather than display: none, to not shift other elements around.

Also removed a redundant parameter from Internals::serializeNavigationMarkup.

R=abarth
BUG=370696

Review URL: https://codereview.chromium.org/476553002

git-svn-id: svn://svn.chromium.org/blink/trunk@180318 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove CSSTouchAction runtime flag (status=stable)

BUG=402536,352134

Review URL: https://codereview.chromium.org/477593002

git-svn-id: svn://svn.chromium.org/blink/trunk@180319 bbb929c8-8fbe-4397-9dbb-9b2b20218538