Adding GetMoreGeneralElementsKind in elements-kind.h

src/elements-kind.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_ELEMENTS_KIND_H_
 #define V8_ELEMENTS_KIND_H_
 
 #include "src/base/macros.h"
 #include "src/checks.h"
 
@@ skipping 193 matching lines @@
   return (GetHoleyElementsKind(from_kind) == to_kind) ||
       (IsFastSmiElementsKind(from_kind) &&
        IsFastObjectElementsKind(to_kind));
 }
 
 
 bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
                                          ElementsKind to_kind);
 
 
+inline ElementsKind GetMoreGeneralElementsKind(ElementsKind from_kind,
+                                               ElementsKind to_kind) {
+  if (IsMoreGeneralElementsKindTransition(from_kind, to_kind)) {
+    return to_kind;
+  }
+  return from_kind;
+}
+
+
 inline bool IsTransitionableFastElementsKind(ElementsKind from_kind) {
   return IsFastElementsKind(from_kind) &&
       from_kind != TERMINAL_FAST_ELEMENTS_KIND;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ELEMENTS_KIND_H_