[DO NOT MERGE] Wait for preloading images to complete before inflating notifications am: 2a2da8935a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21611506

Change-Id: I89e54fb3147bd3e4c810301a75355ae993262b05
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>