Tested this issue on reported chrome version 67.0.3396.99  and latest chrome stable 68.0.3440.106 using Windows 10.Attaching screen-cast for reference.
Steps: 
---------
1. Launched reported chrome 
2. Enabled extension >> legacy browser support 
3. Clicked on extension 
As Observed the chrome browser behavior for 6 hrs and we have not seen any hang in the browser  

@Reporter: Could you please review the attached screen-cast and confirm if anything being missed here.Could you please upgrade to latest chrome stable 68.0.3440.106, you can download latest chrome builds here:" https://www.chromium.org/getting-involved/dev-channel ".

Thanks..!

Deleted: 874622.mp4 3.0 MB

	874622.mp4 3.0 MB View Download

@phanindra.mandapaka@chromium.org The steps to reproduce the issue was a bit off.

1. While using chrome, enter in a URL that is setup in the Chrome ADMX policies to transition that URL to IE.
2. The transition from chrome -> IE hangs

Expected behavior:

The transition from Chrome -> IE to transition to IE without hanging.

From what we have seen from a profile trace it seems that the parent process of Chrome stops communicating over the named pipe.  The only thing that seems to resolve the hanging transition is terminating all chrome processes, then relaunching chrome.   It works for a period of time, then returns back to hanging at chrome -> IE transitions.

Hoping enterprise folks may have an idea on where to route this

Assign to the owner of LBS.

Hi, thanks for reporting the issue. I am one of the developers for LBS and would try to figure this out. 

One thing I notice in the original report is that you mentioned the LBS native host is at version 5.3. Menawhile this should also have updated to 5.4. Do you still observe the same issue after this update. 

One more question is has this issue started appearing without any configuration changes to either Chrome/LBS or IE? Maybe some third party AV/DLP software is interfering?

Lastly you mentioned looking at perf traces. Do you mind WPA traces? Would you be willing to share those with us over a private channel like email or drive share? It will help us analyze the issue. 

PS. It seems this is not Chrome related so the Chrome milestone is not relevant for this bug.

I don't believe we have tried the 5.4 LBS Native Host (MSI).  At the time, I could only get 5.3.

This issue started happening after a chrome update.  We also noticed that it happened when the actual Google Legacy Browser Support extension was updated.  As far as I know, there is no way to downgrade to a lower version of the extension to confirm if that was the issue or not.

I was using the built-in chrome performance traces.  Is there a command line you would like me to utilize to get the data you need from a WPA perspective?

To elaborate a bit more, I am not certain it was a chrome update causing it.  We reverted back to chrome 65 (the version we didn't have any reports of issues on) and still had issues.  This leads be to believe it had something to do with the chrome extension of LBS itself.

Please check this article https://support.google.com/chrome/a/answer/9025467?hl=en and more precisely the ETW section about how to capture performance traces of LBS. It will actually capture all involved processes and help pinpoint the issue well. Just consider sharing the traces through a private channel like drive or dropbox instead of upload publicly here. You can share with my email if you wish pastarmovj at chromium.org. 

Thanks for the shared information. We will analyze it and see if we can figure out why is LBS causing the slow down you describe.