Get rid of createTemporaryProfile method

After this change there is no such thing as temporary profile, each profile header is created once and populated with new data as it arrives. The profile header instance stays the same.

BUG=324769
R=alph@chromium.org

Review URL: https://codereview.chromium.org/106663003

git-svn-id: svn://svn.chromium.org/blink/trunk@163313 bbb929c8-8fbe-4397-9dbb-9b2b20218538