If the user abandons the link after the API request delay (500 ms) but
before the it resolves (~10e3 ms), then the preview shouldn't be
rendered.
Changes:
* actions: Include the link in the FETCH_START, FETCH_FAILED, and
FETCH_END actions.
* reducers: If the active link has changed, then FETCH_END is a NOOP.
Supporting changes:
* reducers: Signal that a preview should be rendered and shown with
preview.shouldShow.
Change-Id: I3dd1c0c566ec63de515174c14845d7927583ce93
Extract core rendering functionality from the mw.popups.renderer and
mw.popups.renderer.article objects.
For now, render and show the preview when the user dwells on and
abandons a link respectively.
Supporting changes:
* Add mw.popups.wait, which is sugar around window.setTimeout.
* action.response -> action.result in the FETCH_END case of the preview
reducer.
Change-Id: I14b437e7c2f55b988837fcb2800dd61a23c29a01
