There is already non-throwing version FrameMirror.restart and RestartFrame in the livedit-debugger.js just adds a throwing wrapper around it.
Also NEEDS_STEP_IN_PROPERTY_NAME was removed, the client code can decide based on the stack_modified field if "step in" is required.
Chromium side was fixed in https://codereview.chromium.org/1249013002/
BUG=None
LOG=N
Review URL: https://codereview.chromium.org/1247363002
Cr-Commit-Position: refs/heads/master@{#29797}
