Use collector specific helper classes

Changed to use inner classes. Also changed some visitors to lambdas.

Bug: 29413717
Bug: 19534862

(cherry picked from commit a07f55913824ab4215a9a4f827fa9c043c0d44d9)

Change-Id: I631c8bfe5f795eda4623c5bb4f357f2dd12358e2
9 files changed