Implement WebStorageArea::containsItem(key) in chrome and drt/test_shell.

webkit/dom_storage/dom_storage_map.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/dom_storage/dom_storage_map.h"
 
 #include "base/logging.h"
 
 namespace {
 
@@ skipping 43 matching lines @@
   return NullableString16(key_iterator_->first, false);
 }
 
 NullableString16 DomStorageMap::GetItem(const string16& key) const {
   ValuesMap::const_iterator found = values_.find(key);
   if (found == values_.end())
     return NullableString16(true);
   return found->second;
 }
 
+bool DomStorageMap::ContainsItem(const string16& key) const {
+  return values_.find(key) != values_.end();
+}
+
 bool DomStorageMap::SetItem(
     const string16& key, const string16& value,
     NullableString16* old_value) {
   ValuesMap::const_iterator found = values_.find(key);
   if (found == values_.end())
     *old_value = NullableString16(true);
   else
     *old_value = found->second;
 
   size_t old_item_size = old_value->is_null() ?
@@ skipping 39 matching lines @@
   copy->ResetKeyIterator();
   return copy;
 }
 
 void DomStorageMap::ResetKeyIterator() {
   key_iterator_ = values_.begin();
   last_key_index_ = 0;
 }
 
 }  // namespace dom_storage