Fraction class prototype and test (not to be committed).

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
diff --git a/runtime/vm/raw_object_snapshot.cc b/runtime/vm/raw_object_snapshot.cc
index c2448a3274a2b1662aba1ff95b3cbeebeed8ccbc..b75701ac1a51ed6519d487127abe4633a1e91091 100644
--- a/runtime/vm/raw_object_snapshot.cc
+++ b/runtime/vm/raw_object_snapshot.cc
@@ -2081,6 +2081,58 @@ void RawBigint::WriteTo(SnapshotWriter* writer,
 }
 
 
+RawFraction* Fraction::ReadFrom(SnapshotReader* reader,
+                                intptr_t object_id,
+                                intptr_t tags,
+                                Snapshot::Kind kind,
+                                bool as_reference) {
+  ASSERT(reader != NULL);
+
+  // Allocate fraction object.
+  Fraction& obj = Fraction::ZoneHandle(reader->zone(), NEW_OBJECT(Fraction));
+  reader->AddBackRef(object_id, &obj, kIsDeserialized);
+
+  // Set all the object fields.
+  READ_OBJECT_FIELDS(obj, obj.raw()->from(), obj.raw()->to(), kAsInlinedObject);
+
+  // If it is a canonical constant make it one.
+  // When reading a full snapshot we don't need to canonicalize the object
+  // as it would already be a canonical object.
+  // When reading a script snapshot or a message snapshot we always have
+  // to canonicalize the object.
+  if (RawObject::IsCanonical(tags)) {
+    if (Snapshot::IsFull(kind)) {
+      // Set the canonical bit.
+      obj.SetCanonical();
+    } else {
+      obj ^= obj.CheckAndCanonicalize(reader->thread(), NULL);
+      ASSERT(!obj.IsNull());
+      ASSERT(obj.IsCanonical());
+    }
+  }
+  return obj.raw();
+}
+
+
+void RawFraction::WriteTo(SnapshotWriter* writer,
+                          intptr_t object_id,
+                          Snapshot::Kind kind,
+                          bool as_reference) {
+  ASSERT(writer != NULL);
+
+  // Write out the serialization header value for this object.
+  writer->WriteInlinedObjectHeader(object_id);
+
+  // Write out the class and tags information.
+  writer->WriteIndexedObject(kFractionCid);
+  writer->WriteTags(writer->GetObjectTags(this));
+
+  // Write out all the object pointer fields.
+  SnapshotWriterVisitor visitor(writer, kAsInlinedObject);
+  visitor.VisitPointers(from(), to());
+}
+
+
 RawDouble* Double::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
                             intptr_t tags,