[bindings] Pass v8::Local<v8::Value> by value in NativeValueTraits<T>::nativeValue()

Source/bindings/tests/results/modules/UnionTypesModules.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file has been auto-generated by code_generator_v8.py. DO NOT MODIFY!
 
 #include "config.h"
 #include "bindings/modules/v8/UnionTypesModules.h"
 
 
@@ skipping 72 matching lines @@
     case BooleanOrString::SpecificTypeBoolean:
         return v8Boolean(impl.getAsBoolean(), isolate);
     case BooleanOrString::SpecificTypeString:
         return v8String(isolate, impl.getAsString());
     default:
         ASSERT_NOT_REACHED();
     }
     return v8::Local<v8::Value>();
 }
 
-BooleanOrString NativeValueTraits<BooleanOrString>::nativeValue(const v8::Local<v8::Value>& value, v8::Isolate* isolate, ExceptionState& exceptionState)
+BooleanOrString NativeValueTraits<BooleanOrString>::nativeValue(v8::Local<v8::Value> value, v8::Isolate* isolate, ExceptionState& exceptionState)
 {
     BooleanOrString impl;
     V8BooleanOrString::toImpl(isolate, value, impl, exceptionState);
     return impl;
 }
 
 } // namespace blink