[AR][IOS] Adds support for .USDZ file extension for ARKit 3D models

Many static file hosting services do not allow setting the appropriate
content-type when serving files. This CL relaxes the requirement to display
USDZ 3D models with ARQuickLook by checking the file extension in addition
to the content type.

Bug: 958938
Change-Id: I1f1a216d3e4f8bbe660242f5acb2eadef0c57509
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1597121
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657726}
6 files changed