Merge "Add String16::c_str and start using it." into main am: 067dbcc1 am:...

Merge "Add String16::c_str and start using it." into main am: 067dbcc1 am: 31d682b3 am: 9e1f6671 am: 8631651c am: 1bfdef88

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2704555



Change-Id: I2bfe798d6667494bfc4431878e49fa637e70ebc2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>