Summary:
Method `computeNotifications` added to the base plugin class.
Plugins should implement this to define a mapping from their state+props to the notifications they are emitting.
I've plugged this into componentDidUpdate, because we don't yet have the background plugin infra. When we do, we'll want some other incoming data hook to use so it's not tied to the react component rendering.
Example usage added to network plugin in the next commit.
Reviewed By: passy
Differential Revision: D10127875
fbshipit-source-id: efd4d8cfc0d3d33852a6cf9a290549a5f90d389d