Chrome Version: (copy from chrome://version)
OS: Chrome

What steps will reproduce the problem?
(1) In tablet mode, open an chrome app with customized caption, for example, Text app
(2) Drag on the caption area

What is the expected result?
The app should be able to be dragged around

What happens instead?
The app can't be dragged


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.