Merge "Don't use String8::empty" into main am: 5f0cfee3c4 am: 5028887aa9

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

Change-Id: Ic7f2ba49e6c5011bce2cd864978306814b7aae38
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>