getInstalledRelatedApps: Add browser-side Mojo service (stub).

third_party/WebKit/LayoutTests/installedapp/resources/installedapp-test-helper.js

 'use strict';
 
 function assert_relatedapplication_equals(actual, expected, description) {
   assert_equals(actual.platform, expected.platform, description);
   assert_equals(actual.url, expected.url, description);
   assert_equals(actual.id, expected.id, description);
 }
 
 function assert_array_relatedapplication_equals(
     actual, expected, description) {
   assert_equals(actual.length, expected.length, description);
 
   for (let i = 0; i < actual.length; i++)
     assert_relatedapplication_equals(actual[i], expected[i], description);
 }
+
+let mockInstalledAppProvider = loadMojoModules(
+    'mockInstalledAppProvider',
+    ['mojo/public/js/bindings',
+     'third_party/WebKit/public/platform/modules/installedapp/installed_app_provider.mojom',
+    ]).then(mojo => {
+  let [bindings, installed_app_provider] = mojo.modules;
+
+  class MockInstalledAppProvider {
+    constructor(interfaceProvider) {
+      this.bindingSet_ =
+          new bindings.BindingSet(installed_app_provider.InstalledAppProvider);
+
+      interfaceProvider.addInterfaceOverrideForTesting(
+          installed_app_provider.InstalledAppProvider.name,
+          handle => this.bindingSet_.addBinding(this, handle));
+    }
+
+    // Returns a Promise that gets rejected if the test should fail.
+    init_() {
+      // sequence of [expectedRelatedApps, installedApps].
+      this.callQueue_ = [];
+
+      return new Promise((resolve, reject) => {this.reject_ = reject});
+    }
+
+    filterInstalledApps(relatedApps) {
+      let callback = null;
+      let result = new Promise(resolve => {callback = resolve;});
+
+      if (!this.callQueue_.length) {
+        this.reject_('Unexpected call to mojo FilterInstalledApps method');
+        return result;
+      }
+
+      let [expectedRelatedApps, installedApps] = this.callQueue_.shift();
+      try {
+        assert_array_relatedapplication_equals(
+            relatedApps, expectedRelatedApps);
+      } catch (e) {
+        this.reject_(e);
+        return result;
+      }
+      callback({installedApps: installedApps});
+
+      return result;
+    }
+
+    pushExpectedCall(expectedRelatedApps, installedApps) {
+      this.callQueue_.push([expectedRelatedApps, installedApps]);
+    }
+  }
+  return new MockInstalledAppProvider(mojo.frameInterfaces);
+});
+
+// Creates a test case that uses a mock InstalledAppProvider.
+// |func| is a function that takes (t, mock), where |mock| is a
+// MockInstalledAppProvider that can have expectations set with
+// pushExpectedCall. It should return a promise, the result of
+// getInstalledRelatedApps().
+// |name| and |properties| are standard testharness arguments.
+function installedapp_test(func, name, properties) {
+  promise_test(t => mockInstalledAppProvider.then(mock => {
+    let mockPromise = mock.init_();
+    return Promise.race([func(t, mock), mockPromise]);
+  }), name, properties);
+}