Merge "media: clarify MediaFormat.KEY_FRAME_RATE for video encoders" into tm-dev am: 42e8a2285c am: 32caee0675

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18605610

Change-Id: I5c8e57917b0b2e2a15d1581216c2de741e6ac652
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>