Merge "Add caching mechanism to speed up midi file reading speed." am: 145a0bec am: be670f47

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/1429788

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Id5a6ebfb5f08180cad4657c256ad152a5390d936