[rialto] Refactor process_request API return type am: 83c974d3d2 am: 6c194eb25f am: 679540a835

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/2775148

Change-Id: Id6407985a1c94eced71b09119a23141b06d12034
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>