Merge "Don't use String8::empty" into main am: 5f0cfee3c4

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

Change-Id: I2ce7655a7aed812afa1a4e430756dbc4bde40a26
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>