Chrome Version: (copy from chrome://version)
OS: (e.g. Win10, MacOS 10.12, etc...)

What steps will reproduce the problem?
(1) On tablet mode, open an app, and open Overview
(2) Tap on the app

What is the expected result?
The app should expand on top of the blurred background.

What happens instead?
Users can see the Homecher showing up in the background: https://photos.app.goo.gl/cJGRRZG2ygKM6Zau7


Please use labels and text to provide additional information.

If this is a regression (i.e., worked before), please consider using the
bisect tool (https://www.chromium.org/developers/bisect-builds-py) to help
us identify the root cause and more rapidly triage the issue.

For graphics-related bugs, please copy/paste the contents of the about:gpu
page at the end of this report.