With the changes in https://chromium-review.googlesource.com/c/chromium/src/+/1145692 applied, some layout tests begin to flake due to weird loading issues. For example, external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-intrinsic-ratio-003v.html fails with pretty high frequency due to some img elements not rendering properly.

It is unclear exactly what is going wrong, but disabling the dispatch changes for ThrottlingURLLoader's URLLoaderClient binding is sufficient to work around the issue. That should be done for now to get the Mojo change landed, but the underlying issue here still needs to be sorted out.