FlameChart: remove obsolete code.

we always record the profile with samples.

BUG=none
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/27019002

git-svn-id: svn://svn.chromium.org/blink/trunk@159450 bbb929c8-8fbe-4397-9dbb-9b2b20218538