DevTools: Async call stacks for FileSystem API part 1 (second try).

This uses a simpler instrumentation API.
First try was in r178149.

BUG=272416, 390863
R=yurys, pfeldman

Review URL: https://codereview.chromium.org/435423004

git-svn-id: svn://svn.chromium.org/blink/trunk@179585 bbb929c8-8fbe-4397-9dbb-9b2b20218538