[iOS] Detect device rotation in NTPVC

Detects device rotation by fixing VC hierarchy.
Removes rotation logic from BVC and handles it in the NTPVC.
Fixes scroll issues when rotating back and forth between landscape and
portrait.
Conditionally sets insets to prevent bug that was previously fixed by
overriding willMoveToParentViewController.

Bug: 1177953
Change-Id: I513aff491c7268b49502756a9208815546c758ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2726541
Commit-Queue: Adam Trudeau-Arcaro <adamta@google.com>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#858784}
GitOrigin-RevId: 1596bfaa21befb618a0d4f79b2570593be683236
5 files changed