Revert "Add dependency visiting methods to BottomUpMutatorContext"
Revert "Add dependency visiting methods to BottomUpMutatorContext"

This reverts commit a2b2080fcd12b9ea302ef9717605aa20abfa6f73.

Dependency visiting methods conflict with the dependency adding methods
already present on BottomUpMutatorContext - mixing calls to visit
dependencies and adding dependencies produces requires hard-to-define
semantics, and complicates parallizing mutators.

Change-Id: I2f793c8db45b97f4d79badc9fe88315fe38d90cd

danw/blueprint,google/blueprint,google/blueprint,danw/blueprint