Merge "Don't use String8::empty" into main am: 5f0cfee3 am: 5028887a am: 94418c8d

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2722496



Change-Id: I80a1578ec30c5294f8934890db8c72707102a68e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>