[automerger skipped] Merge "BufferPool: limit number of idle buffers in...

[automerger skipped] Merge "BufferPool: limit number of idle buffers in caches" am: 4a76ebec am: 55df06ad am: 30321b84 -s ours am: bfb1949f -s ours

am skip reason: Change-Id If3f4433ba1794ccb624b864a56619c8613a315f2 with SHA-1 ea5baf2b is in history

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/1526345

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I41f4b281002ab06b082e64d642198196c28cc944