[Problem/Bug]: window.chrome.webview.postMessage stops working on youtube.com

[seldoff]

What happened?

window.chrome.webview.postMessage stops working when visiting pages on youtube.com. It accepts messages, but these messages never arrive on the native side, i.e., WebMessageReceived event. It works on any other site, e.g., wikipedia.org.

This seems to be caused by something that youtube.com has changed on their side, as it used to work with the same runtime version.

See our investigation results in my comment.

Importance

Important. My app's user experience is significantly compromised.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

135.0.3179.73

SDK Version

1.0.3116

Framework

WPF

Operating System

Windows 11

OS Version

26100.3775

Repro steps

Please use my WebView2Samples fork with the code to reproduce the issue.

• Change BrowserExecutableFolder = "[path to WebView2 135.0.3179.73 runtime]" line in MainWindow.InitializeWebView() to point to the WebView2 135.0.3179.73 runtime directory.
• Start the browser from the IDE and open the debug output window to see the Debug.WriteLine output.
• Visit https://www.wikipedia.org/ and observe WebMessageReceived: {"Initial":true} followed by WebMessageReceived: {"Ping":true} every second.
• Visit https://www.youtube.com/watch?v=vBCrJaLseQc and observe only a single WebMessageReceived: {"Initial":true} message. Ping messages are not coming through. You can check the browser console to see that ping messages are still being sent from the JS side.

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Don't know

Last working version (if regression)

No response

[seldoff]

We think the root cause is the DocumentPolicyIncludeJSCallStacksInCrashReports origin trial that was active in Chromium M133-M135 (inclusive) and triggered by Origin-Trial header on youtube.com. As this trial is not active in M136, WebView2 versions 136.x do not exhibit this issue.

Similarly, passing --origin-trial-disabled-features=DocumentPolicyIncludeJSCallStacksInCrashReports to WebView2 135.0.3179.73 "fixes" the issue.

It is concerning that this origin trial is able to break WebView2 messaging. This indicates there is a bug in WebView2, including versions 136.x and beyond.

[Badhri]

Hi @seldoff Apologies for the delay in response. Somehow we missed this. I happened to try this sample app with v135.0.3179.81 locally and I am able to reproduce the issue. Also tried the same in latest stable and dont hit this(v136)
We will create a tracking bug and work on the same. Thanks for filing this !

[MarkIngramUK]

@Badhri , the origin trial is now being rolled out as a feature in Chromium v137 (see https://chromestatus.com/feature/4731248572628992).

Do you have any information on whether the bug is caused by “Call stacks in crash reports from unresponsive web apps” feature, or from the presence of the origin trial (or presence of any origin trial)?