Introduce [Exposed(Arguments)] in IDL code generator.

Source/bindings/tests/idls/core/TestInterface2.idl

Index: Source/bindings/tests/idls/core/TestInterface2.idl
diff --git a/Source/bindings/tests/idls/core/TestInterface2.idl b/Source/bindings/tests/idls/core/TestInterface2.idl
index 6700cfe34d4bfdbc331ae47557cb63a482df06e6..ce8984319a287c6b4b8ccf205e9ad6394238a1a1 100644
--- a/Source/bindings/tests/idls/core/TestInterface2.idl
+++ b/Source/bindings/tests/idls/core/TestInterface2.idl
@@ -37,6 +37,9 @@
     Constructor,
     DependentLifetime, // Covered by [ActiveDOMObject]
     SetWrapperReferenceFrom=ownerNode, // Conflicts with [SetWrapperReferenceTo]
+    // Note that Exposed(Arguments) has no effect on bindings-tests. It is
+    // processed in generate_global_constructors.py.
+    Exposed(Window FeatureName), // Conflicts with Exposed=(Window,Worker)
 ] interface TestInterface2 {
     // This interface has only runtime enabled constants.
     [RuntimeEnabled=FeatureName] const unsigned short CONST_VALUE_1 = 1;