Add mojo changes for WebXR plane detection

Bug: 954530
Change-Id: Ieb89dc326cae071ed8303736a54698ad82e6ad09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1580139
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Bill Orr <billorr@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Commit-Queue: Piotr Bialecki <bialpio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654315}
13 files changed