Delete TimelineTracingView

Now that corresponding experiment was removed there is no way to see the view. Also removing TimelineFlameChartDataProvider which is not used in tracing based Timeline and we don't show flame chart in other modes.

BUG=361045,394762
R=alph@chromium.org

Review URL: https://codereview.chromium.org/402653002

git-svn-id: svn://svn.chromium.org/blink/trunk@178425 bbb929c8-8fbe-4397-9dbb-9b2b20218538