DevTools: Debugger StepInto/Out/Over initiated from a framework should not black-box it.

BUG=267592
R=yurys, pfeldman@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177170

Review URL: https://codereview.chromium.org/342713002

git-svn-id: svn://svn.chromium.org/blink/trunk@177228 bbb929c8-8fbe-4397-9dbb-9b2b20218538