Windowscommunitytoolkit: Sample app missing overscan boundary on Xbox

[shweaver-MSFT]

Describe the bug

The sample app does not include any considerations for TVs with overscan.

TV Safe Area:
https://docs.microsoft.com/en-us/windows/uwp/design/devices/designing-for-tv#tv-safe-area

• [ ] Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:

Steps to Reproduce

Steps to reproduce the behavior:

1. Deploy the sample app to an Xbox One console with an older TV connected.
2. See lack of TV-Safe boundary. Some content is cut off.

Expected behavior

The sample app should pad interactive content as indicated in the docs:

• 27 epx from the top and bottom
• 48 epx from the left and right sides

Screenshots

If applicable, add screenshots to help explain your problem.

Environment

NuGet Package(s): 

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [X] May 2019 Update (18362)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [X] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] Insider Build (xxxxx)

Device form factor:
- [ ] Desktop
- [X] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [ ] 2017 (version: )
- [X] 2019 (version: ) 
- [ ] 2019 Preview (version: )

Additional context

Add any other context about the problem here.

[msftbot[bot]]

Hello shweaver-MSFT, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌

[shweaver-MSFT]

Inspiration: https://github.com/shweaver-MSFT/TVSafePanel

[michael-hawker]

Thanks @shweaver-MSFT! I could see a nifty MarkupExtension that returns a Thickness value for this being handy to use on any sort of UIElement. 🙂