[automerger skipped] Rename HotwordAudioStreamManager and add Javadoc am: 714691fc46 am: 7da11bed7e -s ours

am skip reason: Merged-In I43a24b27983838e0ef9798eef2f45d1d4b1c9ac8 with SHA-1 585c555cc9 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20618388

Change-Id: I26bf81570a54cd20ae612f7887222caf53607187
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>