Merge "Don't use String8::empty" into main am: 5b401d3b88 am: 280d7677fd am: f70ed8f5a5 am: 89dc578326

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2707674

Change-Id: I14657864922d62414cef66c368b79ce64ae8928d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>