Merge "Allow populating left_icon independently of right_icon." into sc-dev...

Merge "Allow populating left_icon independently of right_icon." into sc-dev am: cd86f384 am: 83bfee7e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/14519486

Change-Id: I4515cfd7d3c05c9755c23ac621f957447e4d172f