Implement platform deleters per spec.

Source/core/dom/DOMStringMap.h

 /*
  * Copyright (C) 2010 Apple 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 30 matching lines @@
 public:
     virtual ~DOMStringMap();
 
     virtual void ref() = 0;
     virtual void deref() = 0;
 
     virtual void getNames(Vector<String>&) = 0;
     virtual String item(const String& name) = 0;
     virtual bool contains(const String& name) = 0;
     virtual void setItem(const String& name, const String& value, ExceptionState&) = 0;
-    virtual void deleteItem(const String& name, ExceptionState&) = 0;
+    virtual bool deleteItem(const String& name) = 0;
     bool anonymousNamedSetter(const String& name, const String& value, ExceptionState& exceptionState)
     {
         setItem(name, value, exceptionState);
         return true;
     }
-    bool anonymousNamedDeleter(const AtomicString& name, ExceptionState&)
+    bool anonymousNamedDeleter(const AtomicString& name, bool& result)
     {
-        // FIXME: Remove ExceptionState parameter.
-
-        TrackExceptionState exceptionState;
-        deleteItem(name, exceptionState);
-        bool result = !exceptionState.hadException();
-        // DOMStringMap deleter should ignore exception.
-        // Behavior of Firefox and Opera are same.
-        // delete document.body.dataset["-foo"] // false instead of DOM Exception 12
-        // LayoutTests/fast/dom/HTMLSelectElement/select-selectedIndex-multiple.html
+        result = deleteItem(name);
         return result;
     }
     void namedPropertyEnumerator(Vector<String>& names, ExceptionState&)
     {
         getNames(names);
     }
     bool namedPropertyQuery(const AtomicString&, ExceptionState&);
 
     String anonymousIndexedGetter(uint32_t index)
     {
         return item(String::number(index));
     }
     bool anonymousIndexedSetter(uint32_t index, const String& value, ExceptionState& exceptionState)
     {
         return anonymousNamedSetter(String::number(index), value, exceptionState);
     }
-    bool anonymousIndexedDeleter(uint32_t index, ExceptionState& exceptionState)
+    bool anonymousIndexedDeleter(uint32_t index)
     {
-        return anonymousNamedDeleter(AtomicString::number(index), exceptionState);
+        bool result;
+        anonymousNamedDeleter(AtomicString::number(index), result);
+        return true;

[haraken, 2013/12/17 15:59:20]

Don't we want to return |result| ?

[sof, 2013/12/17 16:20:08]

4.7.4.1 (the indexed case) in the spec tells us that we shouldn't fall into any
of the later steps, but always handle the indexed deletion. So returning 'true'
here always is appropriate.

Hmm, looking at 4.7.4.1.5 again, I think we have to extend the signature of the
indexed deleter to also take a bool reference, so that the operation's return
value can be propagated back out to the script. I'll do that.

(An observable example of this would be 'delete element.dataset["1"]' in a
strict context where "data-1" isn't a content attribute, I think.)

     }
 
     virtual Element* element() = 0;
 
 protected:
     DOMStringMap()
     {
         ScriptWrappable::init(this);
     }
 };
 
 } // namespace WebCore
 
 #endif // DOMStringMap_h