DevTools: Remove calls of WebInspector.timelineManager and WebInspector.cpuProfilerModel from ScreencastView

BUG=

Review URL: https://codereview.chromium.org/408853003

git-svn-id: svn://svn.chromium.org/blink/trunk@178572 bbb929c8-8fbe-4397-9dbb-9b2b20218538