[Android] ScrollView Performance is worse when page is not the root

Description

Issue originally reported by @mikescandy: https://twitter.com/mikescandy/status/1072985823006605314

Steps to Reproduce

1. Use https://github.com/mikescandy/ScrollTest
2. Compare the modal loading/scrolling time to the non-modal loading/scrolling time.

Expected Behavior

Performance is the same regardless of how the page is served.

Actual Behavior

Performance appears degraded when the page is modal.

Basic Information

• Version with issue: 4.0.0.8055-pre1
• Last known good version:
• IDE:
• Platform Target Frameworks:
  • iOS:
  • Android:
  • UWP:
• Android Support Library Version:
• Nuget Packages:
• Affected Devices:

Screenshots

see Twitter link

Reproduction Link

https://github.com/mikescandy/ScrollTest