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

content/renderer/dom_storage/webstoragearea_impl.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 "content/renderer/dom_storage/webstoragearea_impl.h"
 
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
@@ skipping 41 matching lines @@
 }
 
 WebString WebStorageAreaImpl::key(unsigned index) {
   return cached_area_->GetKey(connection_id_, index);
 }
 
 WebString WebStorageAreaImpl::getItem(const WebString& key) {
   return cached_area_->GetItem(connection_id_, key);
 }
 
+bool WebStorageAreaImpl::containsItem(const WebString& key) {
+  return cached_area_->ContainsItem(connection_id_, key);
+}
+
 void WebStorageAreaImpl::setItem(
     const WebString& key, const WebString& value, const WebURL& page_url,
     WebStorageArea::Result& result) {
   if (!cached_area_->SetItem(connection_id_, key, value, page_url))
     result = ResultBlockedByQuota;
   else
     result = ResultOK;
 }
 
 void WebStorageAreaImpl::removeItem(
     const WebString& key, const WebURL& page_url) {
   cached_area_->RemoveItem(connection_id_, key, page_url);
 }
 
 void WebStorageAreaImpl::clear(const WebURL& page_url) {
   cached_area_->Clear(connection_id_, page_url);
 }