Handlify JSObject::MigrateInstance and friends.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 3d3c0e4e2c6dd0cdcd69e3cff8e9d3410cb05338..d0667e28f14d572a022aa7756a98f3edf63b9a83 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2172,10 +2172,13 @@ class JSObject: public JSReceiver {
   // passed map. This also extends the property backing store if necessary.
   static void AllocateStorageForMap(Handle<JSObject> object, Handle<Map> map);
 
+  // Migrates the given object to a map whose field representations are the
+  // lowest upper bound of all known representations for that field.
   static void MigrateInstance(Handle<JSObject> instance);
 
+  // Migrates the given object only if the target map is already available,
+  // or returns an empty handle if such a map is not yet available.
   static Handle<Object> TryMigrateInstance(Handle<JSObject> instance);
-  inline MUST_USE_RESULT MaybeObject* TryMigrateInstance();
 
   // Can cause GC.
   MUST_USE_RESULT MaybeObject* SetLocalPropertyIgnoreAttributesTrampoline(
@@ -2469,8 +2472,8 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT MaybeObject* TransitionElementsKind(ElementsKind to_kind);
   MUST_USE_RESULT MaybeObject* UpdateAllocationSite(ElementsKind to_kind);
 
+  // TODO(mstarzinger): Both public because of ConvertAnsSetLocalProperty().
   static void MigrateToMap(Handle<JSObject> object, Handle<Map> new_map);
-  MUST_USE_RESULT MaybeObject* MigrateToMap(Map* new_map);
   static void GeneralizeFieldRepresentation(Handle<JSObject> object,
                                             int modify_index,
                                             Representation new_representation,