Merge "Add mobi extensions to known mime types" am: 806aa0b377 am: 08715462b9

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1514851

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I3a9799552789c2a74429de97d4ec572fa86afba2