GitLab

Add PageRead to PageAccessibilityConfiguration so pages can be marked
read-only.

Matching CL in V8:
https://chromium-review.googlesource.com/c/v8/v8/+/1006756

Bug: v8:7464
Change-Id: I9acdd9d5c00db9b89b1a2103be83fa2dde257b37
Reviewed-on: https://chromium-review.googlesource.com/1013564Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553513}