Move declarative API into events API

chrome/renderer/resources/extensions/utils.js

+// 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.
+
+function forEach(dict, f) {
+  for (key in dict) {
+    if (dict.hasOwnProperty(key))
+      f(key, dict[key]);
+  }
+}
+
+// Assuming |array_of_dictionaries| is structured like this:
+// [{id: 1, ... }, {id: 2, ...}, ...], you can use
+// lookup(array_of_dictionaries, 'id', 2) to get the dictionary with id == 2.
+function lookup(array_of_dictionaries, field, value) {
+  var filter = function (dict) {return dict[field] == value;};
+  var matches = array_of_dictionaries.filter(filter);
+  if (matches.length == 0) {
+    return undefined;
+  } else if (matches.length == 1) {
+    return matches[0]
+  } else {
+    throw new Error("Failed lookup of field '" + field + "' with value '" +
+                    value + "'");
+  }
+}
+
+exports.forEach = forEach;
+exports.lookup = lookup;