Implement platform deleters per spec.

Source/core/dom/DOMStringMap.h

Index: Source/core/dom/DOMStringMap.h
diff --git a/Source/core/dom/DOMStringMap.h b/Source/core/dom/DOMStringMap.h
index 22ce97497f1d8f1e8c2f263057966803eb0719af..73096131151eeb045ca13484e92edcdf424a5dd2 100644
--- a/Source/core/dom/DOMStringMap.h
+++ b/Source/core/dom/DOMStringMap.h
@@ -48,23 +48,15 @@ public:
     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&)
@@ -81,9 +73,11 @@ public:
     {
         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;