Generalize HeapObject alignment requirements.

src/snapshot/serialize.cc

Index: src/snapshot/serialize.cc
diff --git a/src/snapshot/serialize.cc b/src/snapshot/serialize.cc
index b311f9dcda065c2c3b1f8dad3bfafe383e7f2a92..4b06b9a6874a6461b859eca6e304a1f864daf47a 100644
--- a/src/snapshot/serialize.cc
+++ b/src/snapshot/serialize.cc
@@ -1729,7 +1729,8 @@ void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
     back_reference = serializer_->AllocateLargeObject(size);
   } else {
     bool needs_double_align = false;
-    if (object_->NeedsToEnsureDoubleAlignment()) {
+    // TODO(bbudge): Generalize to other alignment constraints.
+    if (object_->RequiredAlignment() == kDoubleAligned) {
       // Add wriggle room for double alignment padding.
       back_reference = serializer_->Allocate(space, size + kPointerSize);
       needs_double_align = true;