Merge "Icon: make Icon's Bitmaps immutable" into tm-dev am: 22708575

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17803565



Change-Id: I8f3e8b5e5ab9e987a570dc4d168c82d02faf003d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>