Also clear required_size if successful am: 5c5743f6c6 am: 047323b2bf

Change-Id: I7b6fc024f84efd54021b35c1f2c3dbc9bd28826f
diff --git a/dynamic_partition_control_android.cc b/dynamic_partition_control_android.cc
index bf31244..20e02ac 100644
--- a/dynamic_partition_control_android.cc
+++ b/dynamic_partition_control_android.cc
@@ -493,8 +493,13 @@
     }
   }
 
-  return PrepareDynamicPartitionsForUpdate(
-      source_slot, target_slot, manifest, delete_source);
+  TEST_AND_RETURN_FALSE(PrepareDynamicPartitionsForUpdate(
+      source_slot, target_slot, manifest, delete_source));
+
+  if (required_size != nullptr) {
+    *required_size = 0;
+  }
+  return true;
 }
 
 namespace {