Improve apps v2 upgrade UX

remoting/webapp/unittests/chrome_mocks.js

 // Copyright 2014 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.
 
 // This file contains various mock objects for the chrome platform to make
 // unit testing easier.
 
 Entry = function() {};
 
 (function(scope){
@@ skipping 29 matching lines @@
   this.onMessage = new chromeMocks.Event();
   this.onDisconnect = new chromeMocks.Event();
 
   this.name = '';
   this.sender = null;
 };
 
 chromeMocks.runtime.Port.prototype.disconnect = function() {};
 chromeMocks.runtime.Port.prototype.postMessage = function() {};
 
+chromeMocks.storage = {};
+
+// Sample implementation of chrome.StorageArea according to
+// https://developer.chrome.com/apps/storage#type-StorageArea
+chromeMocks.StorageArea = function() {
+  this.storage_ = {};
+};
+
+function deepCopy(value) {
+  return JSON.parse(JSON.stringify(value));
+}
+
+function getKeys(keys) {
+  if (typeof keys === 'string') {
+    return [keys];
+  } else if (typeof keys === 'object') {
+    return Object.keys(keys);
+  }
+  return [];
+}
+
+chromeMocks.StorageArea.prototype.get = function(keys, onDone) {
+  if (!keys) {
+    onDone(deepCopy(this.storage_));
+    return;
+  }
+
+  var result = (typeof keys === 'object') ? keys : {};
+  getKeys(keys).forEach(function(key) {
+    if (key in this.storage_) {
+      result[key] = deepCopy(this.storage_[key]);
+    }
+  }, this);
+  onDone(result);
+};
+
+chromeMocks.StorageArea.prototype.set = function(value) {
+  for (var key in value) {
+    this.storage_[key] = deepCopy(value[key]);
+  }
+};
+
+chromeMocks.StorageArea.prototype.remove = function(keys) {
+  getKeys(keys).forEach(function(key) {
+    delete this.storage_[key];
+  }, this);
+};
+
+chromeMocks.StorageArea.prototype.clear = function() {
+  this.storage_ = null;
+};
+
+chromeMocks.storage.local = new chromeMocks.StorageArea();
+
+var originals_ = null;
+
+/**
+ * Activates a list of Chrome components to mock
+ * @param {Array.<string>} components
+ */
+chromeMocks.activate = function(components) {
+  if (originals_) {
+    throw new Error('chromeMocks.activate() can only be called once.');
+  }
+  originals_ = {};
+  components.forEach(function(component) {
+    if (!chromeMocks[component]) {
+      throw new Error('No mocks defined for chrome.' + component);
+    }
+    originals_[component] = chrome[component];
+    chrome[component] = chromeMocks[component];
+  });
+};
+
+chromeMocks.restore = function() {
+  if (!originals_) {
+    throw new Error('You must call activate() before restore().');
+  }
+  for (var components in originals_) {
+    chrome[components] = originals_[components];
+  }
+  originals_ = null;
+};
+
 scope.chromeMocks = chromeMocks;
 
 })(window);