[bindings] Let NativeValueTraits<T>::nativeValue be variadic function and merge various convers…

Source/bindings/core/v8/ScriptValue.cpp

Index: Source/bindings/core/v8/ScriptValue.cpp
diff --git a/Source/bindings/core/v8/ScriptValue.cpp b/Source/bindings/core/v8/ScriptValue.cpp
index b698aa3e555191dfbd4d9283d8f472a74fa9bd31..a77fc48ce6018e30990c2e4d312aeae96eab1b19 100644
--- a/Source/bindings/core/v8/ScriptValue.cpp
+++ b/Source/bindings/core/v8/ScriptValue.cpp
@@ -74,13 +74,6 @@ bool ScriptValue::toString(String& result) const
     return true;
 }
 
-PassRefPtr<JSONValue> ScriptValue::toJSONValue(ScriptState* scriptState) const
-{
-    ASSERT(scriptState->contextIsValid());
-    ScriptState::Scope scope(scriptState);
-    return v8ToJSONValue(scriptState->isolate(), v8Value(), JSONValue::maxDepth);
-}
-
 ScriptValue ScriptValue::createNull(ScriptState* scriptState)
 {
     return ScriptValue(scriptState, v8::Null(scriptState->isolate()));