- Improve typing by introducing PhaseView interface.
- Recalculate scale extent after resizing.
- Fix null sentinel which should have been undefined.

Bug: v8:7327

Change-Id: I06881ac3f5681cb419b5da9c6b8aa3a6b2652088
Reviewed-on: https://chromium-review.googlesource.com/1090914Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53631}