- Eliminates *all* copies in the process.
- Moves (nearly) all functionality into Scanner::BookmarkScope.
- Significant code reduction.

[Needs to be rebased once crrev.com/2347883002 lands. All changes in *parser* are from that CL.]

R=marja@chromium.org
BUG=v8:4947

Review-Url: https://codereview.chromium.org/2341323002
Cr-Commit-Position: refs/heads/master@{#39554}