Revert "Align resource timing buffer full processing to spec PR 168 (reland)"

This reverts commit 6dd060768d1c1183e0d29e422a2213f106d98299.

Reason for revert: suspect causing  WebRtcDisableEncryptionFlagBrowserTest.VerifyEncryption to be flaky (FindIt's report)

BUG:chromium:909704

Original change's description:
> Align resource timing buffer full processing to spec PR 168 (reland)
> 
> This change implements the processing model from PR 168[1], when
> it comes to setResourceTimingBufferSize(), clearResourceTimings()
> and the firing of the resourcetimingbufferfull event.
> 
> This is a reland of
> https://chromium-review.googlesource.com/c/chromium/src/+/1345269
> (but with nicer tests).
> 
> [1] https://github.com/w3c/resource-timing/pull/168
> 
> Change-Id: I10431bfda7f79b484c7ee5c608bb8a360d905339
> Bug: 908181, 908414
> Reviewed-on: https://chromium-review.googlesource.com/c/1350950
> Reviewed-by: Nicolás Peña Moreno <npm@chromium.org>
> Commit-Queue: Yoav Weiss <yoavweiss@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#611174}

TBR=npm@chromium.org,yoavweiss@chromium.org

Change-Id: Ia4bf26c6be1e7c4ae35b904bac25fe031f854604
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 908181, 908414
Reviewed-on: https://chromium-review.googlesource.com/c/1354123
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Ned Nguyen <nednguyen@google.com>
Cr-Commit-Position: refs/heads/master@{#611722}
28 files changed