Fix IOOBE due to internal list being updated from remove

This CL removes all prepareChildren(), leaving
only the one in onMeasure(). This makes the state
more stable since we will only update it within a
layout pass. This also reduces any unnecessary work.

BUG: 30252077
BUG: 31303652

Change-Id: Ibd00a3c3ede1dd654b0ed6d1d8d8d1c8da94e57a
(cherry picked from commit 2f517207503fdffbcf930584a37b4a03392755d6)
2 files changed