Make body size CORS-protected instead of TAO-protected

[chromium-wpt-export-bot]

The transferSize delta remains TAO-protected as it measures
the fetch rather than the resource.

Currently behind a runtime flag, until we discuss this with the
RUM community.

See spec change: whatwg/fetch#1556

Bug: 1404669
Change-Id: I8d6d0e3f8e2dc31597b06f6d7b1e426381463226
Fixes: 1404669
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4135873
Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
Commit-Queue: Noam Rosenthal <nrosenthal@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1091399}

---

Closed by @nihardamar because the Chromium CL was reverted before this was landed. Revert:

Revert "Make body size CORS-protected instead of TAO-protected"

This reverts commit 3a8f3fd8736b1721535af5aa148996a2767079e3.

Reason for revert: cause tree close: https://ci.chromium.org/ui/p/chromium/builders/ci/linux-cfm-rel/36567/overview

Original change's description:
> Make body size CORS-protected instead of TAO-protected
>
> The transferSize delta remains TAO-protected as it measures
> the fetch rather than the resource.
>
> Currently behind a runtime flag, until we discuss this with the
> RUM community.
>
> See spec change: https://github.com/whatwg/fetch/pull/1556
>
> Bug: 1404669
> Change-Id: I8d6d0e3f8e2dc31597b06f6d7b1e426381463226
> Fixes: 1404669
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4135873
> Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
> Commit-Queue: Noam Rosenthal <nrosenthal@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1091399}

Bug: 1404669
Change-Id: Ieb987fca2038b9c6daa57875a02e7d82ab673cf6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4156734
Reviewed-by: Tom Lukaszewicz <tluk@google.com>
Owners-Override: Tom Lukaszewicz <tluk@google.com>
Commit-Queue: Victor Tan <victortan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1091414}

[wpt-pr-bot]

The review process for this patch is being conducted in the Chromium project.