Prefer vendor prop when fetching ab partition list am: 996766a950 am: 16ff6de8e1 am: f9a11a3407

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2597086

Change-Id: I0d16415dcc98e14dd19f7a48ff0c4c3b45eba4b6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/payload_consumer/partition_update_generator_android.cc b/payload_consumer/partition_update_generator_android.cc
index 4467182..8a2e9f9 100644
--- a/payload_consumer/partition_update_generator_android.cc
+++ b/payload_consumer/partition_update_generator_android.cc
@@ -110,7 +110,11 @@
 std::vector<std::string>
 PartitionUpdateGeneratorAndroid::GetAbPartitionsOnDevice() const {
   auto partition_list_str =
-      android::base::GetProperty("ro.product.ab_ota_partitions", "");
+      android::base::GetProperty("ro.vendor.build.ab_ota_partitions", "");
+  if (partition_list_str.empty()) {
+    partition_list_str =
+        android::base::GetProperty("ro.product.ab_ota_partitions", "");
+  }
   return base::SplitString(partition_list_str,
                            ",",
                            base::TRIM_WHITESPACE,