Can confirm, no YouTube videos are loading for me.

Oddly enough, if I go incognito, the videos load just fine.

Able to reproduce the issue on reported version 72.0.3616.0(with #out-of-blink-cors flag enabled) using Mac 10.12.6, Ubuntu 14.04 and Windows-10, hence providing Bisect Info

Note: With default chrome settings unable to reproduce the issue on chrome reported version and on #72.0.3614.0. But, with "#out-of-blink-cors" flag enabled able to reproduce the issue on reported version and on #72.0.3614.0. On enabling "out-of-blink-cors" flag in chrome://flags, able to play the YouTube video in earlier chrome versions, hence providing below bisect range and change-log by enabling "out-of-blink-cors" flag.

Bisect Info:
================
Good build: 64.0.3256.0
Bad build: 64.0.3257.0

You are probably looking for a change made after 513424 (known good), but no later than 513425 (first known bad).
https://chromium.googlesource.com/chromium/src/+log/aa8a267bcfcd8a454b57c69012c6c95c6f612d22..b463fdc0bafb4e9e3a1da7f78a7fad74ebf0e06b
Change-Id: I2ff7af8dc54cf1c519e9c0b44478dace80b8f155
Reviewed-on: https://chromium-review.googlesource.com/735242

@Takashi Toyoshima: Please confirm the issue and help in re-assigning if it is not related to your change.

Thanks!	

 Issue 907261  has been merged into this issue.

This is a known issue that happens only when the experimental feature, OutOfBlinkCors, is enabled. So, let me remove *-70 and *-71 labels.

Since we are running a field trial and trying to enable it on m72, I will keep *-72 flags.

I already work on a fix.

If you open any site and open console from dev tools, you will see that some parts of the web site are blocked by CORS Policy.

Same, Youtube nor fabebook videos are loading for me.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2141c235865db17d233f727b9d4303dafb324d31

commit 2141c235865db17d233f727b9d4303dafb324d31
Author: Takashi Toyoshima <toyoshim@chromium.org>
Date: Thu Nov 22 05:44:03 2018

OOR-CORS: Make VariationsHttpHeadersBrowserTest pass with kOutOfBlinkCORS

Chrome internally uses X-Client-Data header, and this should not
triggers CORS preflight request.

TBR=jochen@chromium.org

Bug: 870173,  907018 
Change-Id: I67f1711b9065223f9e174e207980940e175031e9
Reviewed-on: https://chromium-review.googlesource.com/c/1335076
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610313}
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/chrome/common/google_url_loader_throttle.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/content/browser/loader/resource_dispatcher_host_impl.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/content/renderer/loader/web_url_loader_impl.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/content/renderer/pepper/url_request_info_util.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/services/network/public/cpp/network_ipc_param_traits.h
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/services/network/public/cpp/resource_request.h
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/services/network/url_loader.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/third_party/blink/public/platform/web_url_request.h
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/third_party/blink/renderer/platform/exported/web_url_request.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/third_party/blink/renderer/platform/loader/fetch/resource_request.cc
[modify] https://crrev.com/2141c235865db17d233f727b9d4303dafb324d31/third_party/blink/renderer/platform/loader/fetch/resource_request.h

Probably 72.0.3618.0 will pick up this fix.

 Issue 907606  has been merged into this issue.

 Issue 907652  has been merged into this issue.

 Issue 907942  has been merged into this issue.

 Issue 907953  has been merged into this issue.

Able to reproduce the issue on chrome version build with out fix.
Verified the fix on Mac 10.12.6, Windows-10 and Ubuntu 17.10 using Chrome version #72.0.3619.0 as per the comment #0.
Attaching screencast for reference.
Observed "YouTube videos works correctly with #out-of-blink-cors flag default and enabled"
Hence, the fix is working as expected. 
Adding the verified labels.

Thanks...!!

Deleted: 907018.mp4 3.9 MB

	907018.mp4 3.9 MB View Download

 Issue 908465  has been merged into this issue.