Implement platform deleters per spec.

Source/core/storage/Storage.cpp

 /*
  * Copyright (C) 2008 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 60 matching lines @@
 {
     setItem(name, value, exceptionState);
     return true;
 }
 
 bool Storage::anonymousIndexedSetter(unsigned index, const AtomicString& value, ExceptionState& exceptionState)
 {
     return anonymousNamedSetter(AtomicString::number(index), value, exceptionState);
 }
 
-bool Storage::anonymousNamedDeleter(const AtomicString& name, ExceptionState& exceptionState)
+bool Storage::anonymousNamedDeleter(const AtomicString& name, bool& result, ExceptionState& exceptionState)

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

I'm a bit confused. What's the difference between the |result| parameter and the
returned value? Do we need both?

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

We need to represent three outcomes,

 * property deleted ok.
 * property not deleted (non-configurable or other platform object
restrictions.)
 * property not known (4.7.4.2 does not apply; 4.7.4.3 should happen instead.)

[sof, 2013/12/17 16:24:38]

Forgot to say/ask...if the preference is to encode this via an enum instead,
then we can definitely switch.

[haraken, 2013/12/17 16:51:05]

Thanks for the clarification! enum sounds better to me.

 {
+    result = false;
     bool found = contains(name, exceptionState);
     if (!found || exceptionState.hadException())
         return false;
     removeItem(name, exceptionState);
     if (exceptionState.hadException())
-        return false;
+        return true;
+    result = true;
     return true;
 }
 
 bool Storage::anonymousIndexedDeleter(unsigned index, ExceptionState& exceptionState)
 {
-    return anonymousNamedDeleter(AtomicString::number(index), exceptionState);
+    bool result;
+    anonymousNamedDeleter(AtomicString::number(index), result, exceptionState);
+    return true;
 }
 
 void Storage::namedPropertyEnumerator(Vector<String>& names, ExceptionState& exceptionState)
 {
     unsigned length = this->length(exceptionState);
     if (exceptionState.hadException())
         return;
     names.resize(length);
     for (unsigned i = 0; i < length; ++i) {
         String key = this->key(i, exceptionState);
@@ skipping 11 matching lines @@
 {
     if (name == "length")
         return false;
     bool found = contains(name, exceptionState);
     if (exceptionState.hadException() || !found)
         return false;
     return true;
 }
 
 }