DevTools: Do not show (program) and (idle) JS nodes on timeline

BUG=363976

Review URL: https://codereview.chromium.org/247013006

git-svn-id: svn://svn.chromium.org/blink/trunk@172417 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Enable Scroll Animation for RenderLayerScrollableArea

In Blink, only FrameView scrollbars animation is enabled and serviced.
This patch enables scroll animation for non-mainframe scrollbars (
RenderLayerScrollableArea) and service them.

BUG=575, 299059, 307578, 359028

Review URL: https://codereview.chromium.org/214953004

git-svn-id: svn://svn.chromium.org/blink/trunk@172418 bbb929c8-8fbe-4397-9dbb-9b2b20218538