Summary:
Previously, the back swipe navigation gesture would be enabled when the navigation bar is shown and disabled when the navigation bar is hidden.
This change enables developers to control the back swipe gesture independently of the visibility of the navigation bar. An example use case would be that an app wants to render a custom navigation bar so it sets `navigationBarHidden` to true and it wants to enable the back swipe gesture so it sets `interactivePopGestureEnabled` to true.
**Test plan (required)**
- Created a test app to verify setting `interactivePopGestureEnabled` to `true` and `false` with the navigation bar both hidden and shown.
- Verified prop works in a larger app.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/7369
Differential Revision: D3269304
Pulled By: javache
fb-gh-sync-id: ec4324f6517cec4b4fc4f62c4394dc9208a8af6a
fbshipit-source-id: ec4324f6517cec4b4fc4f62c4394dc9208a8af6a
4d2c72b977