Use dictionaries for context creation attributes. Eliminate custom bindings.

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 2a27746c837fe1bc5ccfa8a2ee30a81cecd121ee..b698aa3e555191dfbd4d9283d8f472a74fa9bd31 100644
--- a/Source/bindings/core/v8/ScriptValue.cpp
+++ b/Source/bindings/core/v8/ScriptValue.cpp
@@ -81,4 +81,9 @@ PassRefPtr<JSONValue> ScriptValue::toJSONValue(ScriptState* scriptState) const
     return v8ToJSONValue(scriptState->isolate(), v8Value(), JSONValue::maxDepth);
 }
 
+ScriptValue ScriptValue::createNull(ScriptState* scriptState)
+{
+    return ScriptValue(scriptState, v8::Null(scriptState->isolate()));
+}
+
 } // namespace blink