IDL: make optional arguments (without default) explicit sometimes

Source/core/dom/DOMTokenList.cpp

 /*
  * Copyright (C) 2010 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
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 103 matching lines @@
         if (containsInternal(AtomicString(tokens[i]))) {
             found = true;
             break;
         }
     }
 
     if (found)
         setValue(removeTokens(value(), tokens));
 }
 
-bool DOMTokenList::toggle(const AtomicString& token, ExceptionState& exceptionState)
+bool DOMTokenList::toggle(const AtomicString& token, Optional<bool> force, ExceptionState& exceptionState)
 {
     if (!validateToken(token, exceptionState))
         return false;
 
     if (containsInternal(token)) {
-        removeInternal(token);
-        return false;
+        if (force.isMissing() || !force.get()) {
+            removeInternal(token);
+            return false;
+        }
+        return true;
+    } else {
+        if (!force.isMissing() && !force.get())
+            return false;
+        addInternal(token);
+        return true;
     }
-    addInternal(token);
-    return true;
-}
-
-bool DOMTokenList::toggle(const AtomicString& token, bool force, ExceptionState& exceptionState)
-{
-    if (!validateToken(token, exceptionState))
-        return false;
-
-    if (force)
-        addInternal(token);
-    else
-        removeInternal(token);
-
-    return force;
 }
 
 void DOMTokenList::addInternal(const AtomicString& token)
 {
     if (!containsInternal(token))
         setValue(addToken(value(), token));
 }
 
 void DOMTokenList::removeInternal(const AtomicString& token)
 {
@@ skipping 82 matching lines @@
                 output.append(' ');
         } else {
             output.append(token); // Step 9
         }
     }
 
     return output.toAtomicString();
 }
 
 } // namespace blink