Plugging in a new ViewHierarchyManager to the new pipeline

NewNotifPipeline spits out a 2d list of notifications with new/improved
filtering, sorting, and grouping. This CL is an effort to plug that new
hotness into the NSSL, and make it testable hopefully.

Bug: 112656837
Test: not yet
Change-Id: I0ad159295cc9825f8ebbe219b4823dde82ef4621