[bindings] Compact ConstantConfiguration by using |union|

Source/bindings/core/v8/V8DOMConfiguration.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 107 matching lines @@
         ConstantTypeDouble,
         ConstantTypeString
     };
 
     // ConstantConfiguration translates into calls to Set() for setting up an
     // object's constants. It sets the constant on both the FunctionTemplate and
     // the ObjectTemplate. PropertyAttributes is always ReadOnly.
     struct ConstantConfiguration {
         ConstantConfiguration& operator=(const ConstantConfiguration&) = delete;
         DISALLOW_ALLOCATION();
+        ConstantConfiguration(const char* const name, unsigned value, ConstantType type)
+            : name(name)
+            , ivalue(value)
+            , type(type) {}
+        ConstantConfiguration(const char* const name, int value, ConstantType type)
+            : name(name)
+            , ivalue(value)
+            , type(type) {}
+        ConstantConfiguration(const char* const name, double value, ConstantType type)
+            : name(name)
+            , dvalue(value)
+            , type(type) {}
+        ConstantConfiguration(const char* const name, const char* const value, ConstantType type)
+            : name(name)
+            , svalue(value)
+            , type(type) {}
         const char* const name;
-        int ivalue;
-        double dvalue;
-        const char* const svalue;
+        union {
+            int ivalue;
+            double dvalue;
+            const char* const svalue;
+        };
         ConstantType type;
     };
 
     // Constant installation
     //
     // installConstants and installConstant are used for simple constants. They
     // install constants using v8::Template::Set(), which results in a property
     // that is much faster to access from scripts.
     // installConstantWithGetter is used when some C++ code needs to be executed
     // when the constant is accessed, e.g. to handle deprecation or measuring
@@ skipping 51 matching lines @@
         const AttributeConfiguration*, size_t attributeCount,
         const AccessorConfiguration*, size_t accessorCount,
         const MethodConfiguration*, size_t callbackCount);
 
     static v8::Local<v8::FunctionTemplate> domClassTemplate(v8::Isolate*, WrapperTypeInfo*, void (*)(v8::Local<v8::FunctionTemplate>, v8::Isolate*));
 };
 
 } // namespace blink
 
 #endif // V8DOMConfiguration_h