Reland "Model validation support"

This is a reland of 155e38f8

Removed the browser tests that were failing in chrome OS.

> Model validation support
>
> Introduces a ModelValidator class and adds a command-line switch to
> validate model using ModelValidator. No code is expected to run when the
> command-line switch is not specified.

> Bug: 1219668
> Change-Id: I12f93956b4657bb9997b772a797f1e37d2e99a03
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2999073


> Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
> Reviewed-by: Sophie Chang <sophiechang@chromium.org>
> Commit-Queue: rajendrant <rajendrant@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#908596}

Bug: 1219668
Change-Id: I1f5643215942902d2920a04b84697c6b3b7ec112
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3111963


Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915065}