DevTools: merge TracingTimelineUIUtils into TimelineUIUtils

BUG=428700,387546

Review URL: https://codereview.chromium.org/713913002

git-svn-id: svn://svn.chromium.org/blink/trunk@185113 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: [Elements] Highlight DOM updates

R=vsevik
BUG=424085

Review URL: https://codereview.chromium.org/701153002

git-svn-id: svn://svn.chromium.org/blink/trunk@185115 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Support timeline JS sampling for all threads.

BUG=363976

Review URL: https://codereview.chromium.org/622843002

git-svn-id: svn://svn.chromium.org/blink/trunk@185121 bbb929c8-8fbe-4397-9dbb-9b2b20218538