Revert of Introduce instance type for transition arrays.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index df56d5ce5b14260ad439532e45f1ceda5cb473ca..b39bf682c3d9db8a14fb02740c95547735a14182 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -134,14 +134,6 @@
 }
 
 
-bool Object::IsFixedArray() const {
-  if (!IsHeapObject()) return false;
-  InstanceType instance_type = HeapObject::cast(this)->map()->instance_type();
-  return instance_type == FIXED_ARRAY_TYPE ||
-         instance_type == TRANSITION_ARRAY_TYPE;
-}
-
-
 // External objects are not extensible, so the map check is enough.
 bool Object::IsExternal() const {
   return Object::IsHeapObject() &&
@@ -725,9 +717,9 @@
 TYPE_CHECKER(JSWeakSet, JS_WEAK_SET_TYPE)
 TYPE_CHECKER(JSContextExtensionObject, JS_CONTEXT_EXTENSION_OBJECT_TYPE)
 TYPE_CHECKER(Map, MAP_TYPE)
+TYPE_CHECKER(FixedArray, FIXED_ARRAY_TYPE)
 TYPE_CHECKER(FixedDoubleArray, FIXED_DOUBLE_ARRAY_TYPE)
 TYPE_CHECKER(WeakFixedArray, FIXED_ARRAY_TYPE)
-TYPE_CHECKER(TransitionArray, TRANSITION_ARRAY_TYPE)
 
 
 bool Object::IsJSWeakCollection() const {
@@ -745,6 +737,11 @@
 
 bool Object::IsLayoutDescriptor() const {
   return IsSmi() || IsFixedTypedArrayBase();
+}
+
+
+bool Object::IsTransitionArray() const {
+  return IsFixedArray();
 }
 
 
@@ -2409,7 +2406,7 @@
 
 void FixedArray::set(int index, Object* value) {
   DCHECK_NE(GetHeap()->fixed_cow_array_map(), map());
-  DCHECK(IsFixedArray());
+  DCHECK_EQ(FIXED_ARRAY_TYPE, map()->instance_type());
   DCHECK(index >= 0 && index < this->length());
   int offset = kHeaderSize + index * kPointerSize;
   WRITE_FIELD(this, offset, value);
@@ -4459,8 +4456,7 @@
   if (instance_size != kVariableSizeSentinel) return instance_size;
   // Only inline the most frequent cases.
   InstanceType instance_type = map->instance_type();
-  if (instance_type == FIXED_ARRAY_TYPE ||
-      instance_type == TRANSITION_ARRAY_TYPE) {
+  if (instance_type == FIXED_ARRAY_TYPE) {
     return FixedArray::SizeFor(
         reinterpret_cast<FixedArray*>(this)->synchronized_length());
   }