Merge "Swap contexts when unmapping ExternalTextures" into sc-dev am: 95c0a889 am: 93371499 am: 9eaeaa95

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/15020077

Change-Id: If67bb07d270ba2e9f5fd49063315a1db9b6ae3b0