Chromium 112 does not appear to set embedded iframe as WindowClient

[guest271314]

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[guest271314]

The cause of https://github.com/guest271314/persistent-serviceworker/tree/main/chromium_extension_web_accessible_resources_iframe_message_event not working as expected on Chromium 112 is evidently rooted in at chrome://flags

Experimental third-party storage partitioning.
Enables partitioning of third-party storage by top-level site. Note: this is under active development and may result in unexpected behavior. Please file bugs at https://bugs.chromium.org/p/chromium/issues/entry?labels=StoragePartitioning-trial-bugs&components=Blink%3EStorage. – Mac, Windows, Linux, ChromeOS, Android, Fuchsia, Lacros

#third-party-storage-partitioning

See privacycg/storage-partitioning#25 https://groups.google.com/a/chromium.org/g/net-reviews/c/itOHk-vM8r8.

Either disable at chrome://flags or launch with --disable-features=ThirdPartyStoragePartitioning flag and the message event approach works as expected.