Simplify PrepareForDataProperty in the IsElement case

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 5748 matching lines @@
                                          Representation new_representation,
                                          Handle<HeapType> new_field_type,
                                          StoreMode store_mode);
   static Handle<Map> CopyGeneralizeAllRepresentations(
       Handle<Map> map, int modify_index, StoreMode store_mode,
       PropertyKind kind, PropertyAttributes attributes, const char* reason);
 
   static Handle<Map> PrepareForDataProperty(Handle<Map> old_map,
                                             int descriptor_number,
                                             Handle<Object> value);
-  static Handle<Map> PrepareForDataElement(Handle<Map> old_map,
-                                           Handle<Object> value);
 
   static Handle<Map> Normalize(Handle<Map> map, PropertyNormalizationMode mode,
                                const char* reason);
 
   // Returns the constructor name (the name (possibly, inferred name) of the
   // function that was used to instantiate the object).
   String* constructor_name();
 
   // Tells whether the map is used for JSObjects in dictionary mode (ie
   // normalized objects, ie objects for which HasFastProperties returns false).
@@ skipping 242 matching lines @@
 
   bool CanTransition() {
     // Only JSObject and subtypes have map transitions and back pointers.
     STATIC_ASSERT(LAST_TYPE == LAST_JS_OBJECT_TYPE);
     return instance_type() >= FIRST_JS_OBJECT_TYPE;
   }
 
   bool IsJSObjectMap() {
     return instance_type() >= FIRST_JS_OBJECT_TYPE;
   }
+  bool IsJSArrayMap() { return instance_type() == JS_ARRAY_TYPE; }
   bool IsStringMap() { return instance_type() < FIRST_NONSTRING_TYPE; }
   bool IsJSProxyMap() {
     InstanceType type = instance_type();
     return FIRST_JS_PROXY_TYPE <= type && type <= LAST_JS_PROXY_TYPE;
   }
   bool IsJSGlobalProxyMap() {
     return instance_type() == JS_GLOBAL_PROXY_TYPE;
   }
   bool IsJSGlobalObjectMap() {
     return instance_type() == JS_GLOBAL_OBJECT_TYPE;
@@ skipping 4753 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_