Adding operator== to TimingFunctionTestHelper.

DEPENDS=https://codereview.chromium.org/60033004/ - Don't check all animation/transition properties when comparing RenderStyles
BUG=

Review URL: https://codereview.chromium.org/60323005

git-svn-id: svn://svn.chromium.org/blink/trunk@161676 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix potential flakiness of svg/custom/repaint-shadow.svg

Makes sure the test runs after font load. A rebaseline is required
because current expectations include repainting caused by font load.

BUG=311469

Review URL: https://codereview.chromium.org/64003003

git-svn-id: svn://svn.chromium.org/blink/trunk@161677 bbb929c8-8fbe-4397-9dbb-9b2b20218538