Record the source build fingerprint in SnapshotMergeStats. am: e2b83494b3

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/update_engine/+/15178752

Change-Id: I5d8e8641fd4083b63354db5e96c97f547c332d05
diff --git a/aosp/cleanup_previous_update_action.cc b/aosp/cleanup_previous_update_action.cc
index dde6b89..5084c1e 100644
--- a/aosp/cleanup_previous_update_action.cc
+++ b/aosp/cleanup_previous_update_action.cc
@@ -409,6 +409,14 @@
   merge_stats_->set_boot_complete_to_merge_start_time_ms(
       merge_start_time.count() - merge_stats_->boot_complete_time_ms());
 
+  auto source_build_fingerprint = snapshot_->ReadSourceBuildFingerprint();
+  merge_stats_->set_source_build_fingerprint(source_build_fingerprint);
+
+  if (!merge_stats_->WriteState()) {
+    LOG(ERROR) << "Failed to write merge stats; record may be unreliable if "
+                  "merge is interrupted.";
+  }
+
   if (snapshot_->InitiateMerge()) {
     WaitForMergeOrSchedule();
     return;