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

webkit/dom_storage/dom_storage_cached_area.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_cached_area.h"
 
 #include "base/basictypes.h"
 #include "webkit/dom_storage/dom_storage_map.h"
 #include "webkit/dom_storage/dom_storage_proxy.h"
 
@@ skipping 19 matching lines @@
   PrimeIfNeeded(connection_id);
   return map_->Key(index);
 }
 
 NullableString16 DomStorageCachedArea::GetItem(
     int connection_id, const string16& key) {
   PrimeIfNeeded(connection_id);
   return map_->GetItem(key);
 }
 
+bool DomStorageCachedArea::ContainsItem(
+    int connection_id, const string16& key) {
+  PrimeIfNeeded(connection_id);
+  return map_->ContainsItem(key);
+}
+
 bool DomStorageCachedArea::SetItem(
     int connection_id, const string16& key,
     const string16& value, const GURL& page_url) {
   // A quick check to reject obviously overbudget items to avoid
   // the priming the cache.
   if (key.length() + value.length() > dom_storage::kPerAreaQuota)
     return false;
 
   PrimeIfNeeded(connection_id);
   NullableString16 unused;
@@ skipping 135 matching lines @@
     ignore_key_mutations_.erase(found);
 }
 
 void DomStorageCachedArea::OnClearComplete(bool success) {
   DCHECK(success);
   DCHECK(ignore_all_mutations_);
   ignore_all_mutations_ = false;
 }
 
 }  // namespace dom_storage