This is regression issue ,broken in 'M 53' and below is narrow bisect:
https://chromium.googlesource.com/chromium/src/+log/2052c61710876afbc63a0ff159509f91a152812b..2ad58be9c95de52a6e6962c83df9099c8084ddae?pretty=fuller&n=1000

Suspecting: r401392

Good build:53.0.2776.0
Bad build:53.0.2778.0

Note: Issue is not seen on Mac and Linux OS as windows get closed.

Kindly help to re-assign, if your changes are not cause for this issue.

Deleted: Actual_hangou.mp4 597 KB

	Actual_hangou.mp4 597 KB View Download

Deleted: Exp_hangout.mp4 1.4 MB

	Exp_hangout.mp4 1.4 MB View Download

Could have this be caused by r401390? It's in the narrow bissect range.

-  // Without --enable-panels, only support Hangouts.
+// Panels are an Eraser target. See http://crbug.com/571511 for details.
+// TODO(dimich): remove the rest of Panels code (except ChromeOS) once
+// erasure is stable.
+#if defined(OS_CHROMEOS)
+  // Without --enable-panels, only support Hangouts on ChromeOS.
   for (const char* id : extension_misc::kHangoutsExtensionIds) {
     if (extension_id == id)
       return true;
   }
+#endif  // OS_CHROMEOS

I believe the bisect is incorrect. The range shows the CL I did that disables Panels (windows glued to the bottom of the screen for Hangouts). It converts them into regular floating windows. The captured video shows the hangout window glued to the bottom of the screen. It can't be with the specified bisect range.

I would suggest getting a better reproducible steps as well. The original bug says it's visible in M55, the bisect points to M53. 

Also, it would be good to know how to get a version of the Hangouts extension that shows that "Upgrade" button because mine doesn't. I can't reproduce the issue locally on M55 build on Windows or Linux.

Is there crash reports associated with this perhaps?

See bug 571511 for more info on Panels removal and Hangout extension update.

dmascarenhas@, can you please update per c#3?

Thank you!

With response to comment #3:

Above is not reproducible as 'Update' button is not visible on the app window using Latest Canary Version:56.0.2889.0 (Official Build) 1e457676004f8af16e0086280b73d87c1e5efba7-refs/heads/master@{#424926}

Resolving Won't Fix since several things happened since then:
- the Upgrade button apparently disappeared form the extension
- the Panels were completely removed from Chrome in M54
- we don't have reproducible case anymore.

Please reactivate with reproducible case attached if needed.