Don't update fragments if the manager's state doesn't change.

Bug 32610133

A change in behavior was introduced in which the dispatch* methods
moved the state of the manager's fragments even when the manager's
state doesn't change.

Test: I88f5a3313ad05429167c417b840f888f86fd1c11

Change-Id: Ie260b1c57fae505b2636ff7572a493a92449dff4