Teach FontDescription about synthetics.

We pass synthetic bold/italic bits separately now, which
means that FontDescription doesn't actually describe the
font data we desire. We should fix that.

R=eae,ksakamoto
BUG=315783

Review URL: https://codereview.chromium.org/63523007

git-svn-id: svn://svn.chromium.org/blink/trunk@161977 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Allow Web Animations flags to be turned off as well as on

This is a first step towards switching to Web Animations as the default
implementation of CSS animations and transitions. When that switch is made, a
virtual test suite will be added to run the animations and transitions
LayoutTests with the legacy animations engine. Those virtual suites will
require a --disable-web-animations-css flag in Chromium, for which this change
is a prerequisite.

BUG=258896
R=abarth@chromium.org, dstockwell@chromium.org, dstockwell

Review URL: https://codereview.chromium.org/66023004

git-svn-id: svn://svn.chromium.org/blink/trunk@161978 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IndexedDB: Expose TimeoutError via blink public API

This will be used by the Chromium back-end to send transaction timeouts.

BUG=318992

Review URL: https://codereview.chromium.org/64543009

git-svn-id: svn://svn.chromium.org/blink/trunk@161979 bbb929c8-8fbe-4397-9dbb-9b2b20218538