Summary:
Not a API change, but this may break the layout of exisitng apps that
uses NavigationHeader.
For now, NavigationHeader uses absolute position, which makes it hard for
NavigationCardStack to determine the height of the scenes.
Theoretically, the height of the scenes would be the height of the cards
stack minus the height of the header.
That said, if we want to support the headers with different height (e.g.
MyIOSHeader or MyAndroidHeader), we're forced to expose the height of the
headers and manually compute the height of the scenes.
Alternatively, if the header does not use absolute position, the height
of the scenes can adjust automatically with flex box, and that's what this
commit is about to do.
Reviewed By: ericvicenti
Differential Revision: D3671119
fbshipit-source-id: 26e48f801da3661c5d7dce4752ba927621172f4a
38979f9c68