Merge "Fix NPE in TTS service if no engine string" into udc-dev am: 987b2e7d35

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24758914

Change-Id: Id6e4d0141593885bab85907847e5bab420cc85c2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>