IDL: make optional arguments (without default) explicit sometimes

Source/core/css/CSSPrimitiveValue.idl

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 36 matching lines @@
     const unsigned short CSS_COUNTER    = 23;
     const unsigned short CSS_RECT       = 24;
     const unsigned short CSS_RGBCOLOR   = 25;
     const unsigned short CSS_VW         = 26;
     const unsigned short CSS_VH         = 27;
     const unsigned short CSS_VMIN       = 28;
     const unsigned short CSS_VMAX       = 29;
 
     readonly attribute unsigned short primitiveType;
 
-     [RaisesException] void setFloatValue([Default=Undefined] optional unsigned short unitType,
-                                      [Default=Undefined] optional float floatValue);
-    [RaisesException] float getFloatValue([Default=Undefined] optional unsigned short unitType);
-     [RaisesException] void setStringValue([Default=Undefined] optional unsigned short stringType,
-                                       [Default=Undefined] optional DOMString stringValue);
+     [RaisesException] void setFloatValue(optional unsigned short unitType,
+                                          optional float floatValue);
+    [RaisesException] float getFloatValue(optional unsigned short unitType);
+     [RaisesException] void setStringValue(optional unsigned short stringType,
+                                           optional DOMString stringValue);
     [RaisesException] DOMString getStringValue();
     [RaisesException] Counter getCounterValue();
     [RaisesException] Rect getRectValue();
     [RaisesException] RGBColor getRGBColorValue();
 };