Collect more COW size data in SnapshotMergeReport. am: 8bda8216db

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1616650

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I76f05505a1be221afe3bb5daf4da28874fa7ece5
diff --git a/aosp/cleanup_previous_update_action.cc b/aosp/cleanup_previous_update_action.cc
index 55c5a73..6eaa35b 100644
--- a/aosp/cleanup_previous_update_action.cc
+++ b/aosp/cleanup_previous_update_action.cc
@@ -395,9 +395,9 @@
     return;
   }
 
-  uint64_t cow_file_size;
-  if (snapshot_->InitiateMerge(&cow_file_size)) {
-    merge_stats_->set_cow_file_size(cow_file_size);
+  snapshot_->UpdateCowStats(merge_stats_);
+
+  if (snapshot_->InitiateMerge()) {
     WaitForMergeOrSchedule();
     return;
   }