WebUI: Move test_browser_proxy.js one level up.

chrome/test/data/webui/test_browser_proxy.js

+// Copyright 2016 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.
+
+/**
+ * A base class for all test browser proxies to inherit from. Provides helper
+ * methods for allowing tests to track when a method was called.
+ *
+ * Subclasses are responsible for calling |methodCalled|, when a method is
+ * called, which will trigger callers of |whenCalled| to get notified.
+ * For example:
+ * --------------------------------------------------------------------------
+ * var MyTestBrowserProxy = function() {
+ *   TestBrowserProxy.call(this, ['myMethod']);
+ * };
+ * MyTestBrowserProxy.prototype = function() {
+ *   __proto__: TestBrowserProxy.prototype,
+ *
+ *   myMethod: function(someId) {
+ *     this.methodCalled('myMethod', someId);
+ *   },
+ * };
+ *
+ * // Test code sample
+ *
+ * var testBrowserProxy = new MyTestBrowserProxy();
+ * // ...Replacing real proxy with test proxy....
+ * simulateClickFooButton();
+ * testBrowserProxy.whenCalled('fooMethod').then(function(id) {
+ *   assertEquals(EXPECTED_ID, id);
+ * });
+ * --------------------------------------------------------------------------
+ *
+ * @constructor
+ * @param {!Array<string>} methodNames Names of all methods whose calls
+ *     need to be tracked.
+ */
+var TestBrowserProxy = function(methodNames) {
+  /** @private {!Map<string, !PromiseResolver>} */
+  this.resolverMap_ = new Map();
+  methodNames.forEach(this.resetResolver, this);
+};
+
+TestBrowserProxy.prototype = {
+  /**
+   * Called by subclasses when a tracked method is called from the code that
+   * is being tested.
+   * @param {string} methodName
+   * @param {*=} opt_arg Optional argument to be forwarded to the testing
+   *     code, useful for checking whether the proxy method was called with
+   *     the expected arguments.
+   * @protected
+   */
+  methodCalled: function(methodName, opt_arg) {
+    this.resolverMap_.get(methodName).resolve(opt_arg);
+  },
+
+  /**
+   * @param {string} methodName
+   * @return {!Promise} A promise that is resolved when the given method
+   *     is called.
+   */
+  whenCalled: function(methodName) {
+    return this.resolverMap_.get(methodName).promise;
+  },
+
+  /**
+   * Resets the PromiseResolver associated with the given method.
+   * @param {string} methodName
+   */
+  resetResolver: function(methodName) {
+    this.resolverMap_.set(methodName, new PromiseResolver());
+  },
+
+  /**
+   * Resets all PromiseResolvers.
+   */
+  reset: function() {
+    this.resolverMap_.forEach(function(value, methodName) {
+      this.resolverMap_.set(methodName, new PromiseResolver());
+    }.bind(this));
+  },
+};