This reverts commit 047bccfac1.
It created merge conflicts with a bunch of patches that were days old and about to be merged. Instead of rebasing 10 patches, let's revert this one, finish merging the other ones and just rebase and fix this one. I'll re-introduce the patch in a bit.
Change-Id: Ib495755b0ab4bfa5fdf5590b1271792862a47d4b
Supporting changes:
* Remove the preview.previousActiveLink property from the state tree as
it's unnecessary.
Change-Id: I657decf9425a7a9e2b27a798ed60b162569661d8
Supporting changes:
* Add mw.popups.registerChangeListener, which registers a change
listener that will only be called when the state in the store has
changed.
Change-Id: Ibe6934058327c7f02f7d8092e74a667a5a1c600a