Cherry-pick: aw: Reset parent draw constraints on tear down

Clean cherry-pick of chromium

BUG: 16948043

Original description:

Without this, the same webview getting attached again but at a different
part of the view tree would be getting stale and completely wrong parent
draw constraints.

A classic example of this is when webview going into full screen video

Change-Id: I9d6eafcb83b5fdee4bd9fe17c0f0392ac2d8fd52
3 files changed