Bug 935473 - Replace ViewGroup.MarginLayoutParams with MarginLayoutParams (r=sriram, a=lsblakk)
Bug 935473 - Avoid unnecessary animations in forward button (r=wesj, a=lsblakk)
Bug 935473 - Factor out method to animate forward button's visibility (r=wesj, a=lsblakk)
Bug 935473 - Update forward button visibility when exiting editing mode (r=wesj, a=lsblakk)