WebUI: Split TestBrowserProxy from TestMock

TestBrowserProxy was intended as a way to stub out BrowserProxy classes,
and to be set up extending an interface, e.g.:

class MyTestBrowserProxy extends TestBrowserProxy implements MyProxy {
}

Later on, the "fromClass()" initializer and related methods were added
in an attempt to transform TestBrowserProxy into a generic mocking
utility. Unfortunately, the need to support the huge number of
existing TestBrowserProxy users of the form above necessitated a few
type hacks, e.g. setting a default type of "any" for the template type
and allowing initialization via a constructor as well as via
fromClass. See
https://bugs.chromium.org/p/chromium/issues/detail?id=1076168#c8
for some initial discussion that came up when the pattern was added.

Moreover, there were several places in the code using TestBrowserProxy
in both ways, generally with a mock-style proxy wrapped inside the
"extends" style proxy. This further demonstrated TestBrowserProxy had
become 2 different classes merged into one (although the two share
some limited functionality, e.g. methodCalled()).

This CL forks TestBrowserProxy into TestBrowserProxy and TestMock,
removes the "fromClass" initializer and related methods from
TestBrowserProxy to make it clear it is intended to be used as above,
and makes the constructor for TestMock private and removes " = any"
to clarify that users wanting the generic mock should initialize it
only with fromClass().

Bug: 1076168
Change-Id: Ic55dd186a5a3835ab9fea2ef8ad96e2b98eeeff5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4232884
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1103346}

chrome/test/data/webui/BUILD.gn

@@ -410,6 +410,7 @@ ts_library("build_ts") {
     "mocked_metrics_reporter.ts",
     "polymer_test_util.ts",
     "test_browser_proxy.ts",
+    "test_mock.ts",
     "test_open_window_proxy.ts",
     "test_plural_string_proxy.ts",
     "test_store_ts.ts",

chrome/test/data/webui/chromeos/cloud_upload/cloud_upload_test_browser_proxy.ts

@@ -4,7 +4,7 @@
 
 import {DialogArgs, DialogPage, DialogTask, PageHandlerRemote} from 'chrome://cloud-upload/cloud_upload.mojom-webui.js';
 import {CloudUploadBrowserProxy} from 'chrome://cloud-upload/cloud_upload_browser_proxy.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 export interface ProxyOptions {
   fileName?: string|null;
@@ -21,10 +21,10 @@ export interface ProxyOptions {
  * mojo responses.
  */
 export class CloudUploadTestBrowserProxy implements CloudUploadBrowserProxy {
-  handler: PageHandlerRemote&TestBrowserProxy;
+  handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
 
   constructor(options: ProxyOptions) {
-    this.handler = TestBrowserProxy.fromClass(PageHandlerRemote);
+    this.handler = TestMock.fromClass(PageHandlerRemote);
     const args: DialogArgs = {
       fileNames: [],
       dialogPage: options.dialogPage,
@@ -52,4 +52,4 @@ export class CloudUploadTestBrowserProxy implements CloudUploadBrowserProxy {
   isTest() {
     return true;
   }
-}
+}

chrome/test/data/webui/chromeos/manage_mirrorsync/manage_mirrorsync_app_test.ts

@@ -10,6 +10,7 @@ import {FolderSelector} from 'chrome://manage-mirrorsync/components/folder_selec
 import {PageHandlerRemote} from 'chrome://manage-mirrorsync/manage_mirrorsync.mojom-webui.js';
 import {assertArrayEquals, assertNotEquals, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {isVisible} from 'chrome://webui-test/test_util.js';
 
 /**
@@ -18,11 +19,11 @@ import {isVisible} from 'chrome://webui-test/test_util.js';
  */
 class ManageMirrorSyncTestBrowserProxy extends TestBrowserProxy implements
     BrowserProxy {
-  handler: PageHandlerRemote&TestBrowserProxy;
+  handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
 
   constructor() {
     super(['getChildFolders']);
-    this.handler = TestBrowserProxy.fromClass(PageHandlerRemote);
+    this.handler = TestMock.fromClass(PageHandlerRemote);
   }
 }
 

chrome/test/data/webui/chromeos/office_fallback/office_fallback_app_test.ts

@@ -8,19 +8,19 @@ import {DialogChoice, PageHandlerRemote} from 'chrome://office-fallback/office_f
 import {OfficeFallbackBrowserProxy} from 'chrome://office-fallback/office_fallback_browser_proxy.js';
 import type {OfficeFallbackElement} from 'chrome://office-fallback/office_fallback_dialog.js';
 import {assertDeepEquals, assertEquals} from 'chrome://webui-test/chai_assert.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 
 /**
  * A test OfficeFallbackBrowserProxy implementation that enables to mock various
  * mojo responses.
  */
 class OfficeFallbackTestBrowserProxy implements OfficeFallbackBrowserProxy {
-  handler: PageHandlerRemote&TestBrowserProxy;
+  handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
   dialogArgs: string;
 
   constructor() {
-    this.handler = TestBrowserProxy.fromClass(PageHandlerRemote);
+    this.handler = TestMock.fromClass(PageHandlerRemote);
     // Creating JSON string as in OfficeFallbackDialog::GetDialogArgs().
     const args = {
       'titleText': 'a title',
@@ -114,4 +114,4 @@ suite('<office-fallback>', () => {
     assertDeepEquals(
         [DialogChoice.kCancel], testProxy.handler.getArgs('close'));
   });
-});
+});

chrome/test/data/webui/chromeos/personalization_app/ambient_preview_large_element_test.ts

@@ -9,7 +9,7 @@ import {AmbientObserver, AmbientPreviewLarge, Paths, PersonalizationRouter, Topi
 import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
 import {assertDeepEquals, assertEquals, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {waitAfterNextRender} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 import {baseSetup, initElement, teardownElement} from './personalization_app_test_utils.js';
 import {TestAmbientProvider} from './test_ambient_interface_provider.js';
@@ -21,7 +21,7 @@ suite('AmbientPreviewLargeTest', function() {
   let ambientProvider: TestAmbientProvider;
   let personalizationStore: TestPersonalizationStore;
   const routerOriginal = PersonalizationRouter.instance;
-  const routerMock = TestBrowserProxy.fromClass(PersonalizationRouter);
+  const routerMock = TestMock.fromClass(PersonalizationRouter);
 
   setup(() => {
     const mocks = baseSetup();

chrome/test/data/webui/chromeos/personalization_app/ambient_preview_small_element_test.ts

@@ -9,7 +9,7 @@ import {AmbientObserver, AmbientPreviewSmall, PersonalizationRouter, TopicSource
 import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
 import {assertEquals, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {waitAfterNextRender} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 import {baseSetup, initElement, teardownElement} from './personalization_app_test_utils.js';
 import {TestAmbientProvider} from './test_ambient_interface_provider.js';
@@ -21,7 +21,7 @@ suite('AmbientPreviewSmallTest', function() {
   let ambientProvider: TestAmbientProvider;
   let personalizationStore: TestPersonalizationStore;
   const routerOriginal = PersonalizationRouter.instance;
-  const routerMock = TestBrowserProxy.fromClass(PersonalizationRouter);
+  const routerMock = TestMock.fromClass(PersonalizationRouter);
 
   setup(() => {
     loadTimeData.overrideValues({isAmbientModeAllowed: true});

chrome/test/data/webui/chromeos/personalization_app/ambient_subpage_element_test.ts

@@ -11,7 +11,7 @@ import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
 import {Url} from 'chrome://resources/mojo/url/mojom/url.mojom-webui.js';
 import {assertDeepEquals, assertEquals, assertFalse, assertNotEquals, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {waitAfterNextRender} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 import {baseSetup, initElement, teardownElement} from './personalization_app_test_utils.js';
 import {TestAmbientProvider} from './test_ambient_interface_provider.js';
@@ -29,7 +29,7 @@ suite('AmbientSubpageTest', function() {
   let ambientProvider: TestAmbientProvider;
   let personalizationStore: TestPersonalizationStore;
   const routerOriginal = PersonalizationRouter.instance;
-  const routerMock = TestBrowserProxy.fromClass(PersonalizationRouter);
+  const routerMock = TestMock.fromClass(PersonalizationRouter);
 
   setup(() => {
     loadTimeData.overrideValues({

chrome/test/data/webui/chromeos/personalization_app/google_photos_albums_element_test.ts

@@ -8,7 +8,7 @@ import 'chrome://webui-test/mojo_webui_test_support.js';
 import {fetchGooglePhotosAlbums, getCountText, GooglePhotosAlbum, GooglePhotosAlbums, initializeGooglePhotosData, PersonalizationActionName, PersonalizationRouter, SetErrorAction, WallpaperGridItem} from 'chrome://personalization/js/personalization_app.js';
 import {assertDeepEquals, assertEquals, assertGT, assertNotEquals} from 'chrome://webui-test/chai_assert.js';
 import {waitAfterNextRender} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 import {baseSetup, createSvgDataUrl, initElement, teardownElement} from './personalization_app_test_utils.js';
 import {TestPersonalizationStore} from './test_personalization_store.js';
@@ -209,7 +209,7 @@ suite('GooglePhotosAlbumsTest', function() {
     });
 
     // Mock singleton |PersonalizationRouter|.
-    const router = TestBrowserProxy.fromClass(PersonalizationRouter);
+    const router = TestMock.fromClass(PersonalizationRouter);
     PersonalizationRouter.instance = () => router;
 
     // Mock |PersonalizationRouter.selectGooglePhotosAlbum()|.

chrome/test/data/webui/cr_components/app_management/app_management_test_support.ts

@@ -6,15 +6,16 @@ import {App, AppType, InstallReason, InstallSource, OptionalBool, PageCallbackRo
 import {BrowserProxy} from 'chrome://resources/cr_components/app_management/browser_proxy.js';
 import {createTriStatePermission} from 'chrome://resources/cr_components/app_management/permission_util.js';
 import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 export class TestAppManagementBrowserProxy extends TestBrowserProxy implements
     BrowserProxy {
   callbackRouter: PageCallbackRouter;
-  handler: PageHandlerRemote&TestBrowserProxy;
+  handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
 
   constructor() {
     super(['recordEnumerationValue']);
-    this.handler = TestBrowserProxy.fromClass(PageHandlerRemote);
+    this.handler = TestMock.fromClass(PageHandlerRemote);
     this.callbackRouter = new PageCallbackRouter();
   }
 

chrome/test/data/webui/cr_components/history_clusters_test.ts

@@ -10,13 +10,13 @@ import {HistoryClustersElement} from 'chrome://resources/cr_components/history_c
 import {Cluster, PageCallbackRouter, PageHandlerRemote, PageRemote, QueryResult, RawVisitData, URLVisit} from 'chrome://resources/cr_components/history_clusters/history_clusters.mojom-webui.js';
 import {assertEquals} from 'chrome://webui-test/chai_assert.js';
 import {flushTasks} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
-let handler: PageHandlerRemote&TestBrowserProxy;
+let handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
 let callbackRouterRemote: PageRemote;
 
 function createBrowserProxy() {
-  handler = TestBrowserProxy.fromClass(PageHandlerRemote);
+  handler = TestMock.fromClass(PageHandlerRemote);
   const callbackRouter = new PageCallbackRouter();
   BrowserProxyImpl.setInstance(new BrowserProxyImpl(handler, callbackRouter));
   callbackRouterRemote = callbackRouter.$.bindNewPipeAndPassRemote();

chrome/test/data/webui/cr_components/most_visited_focus_test.ts

@@ -8,7 +8,7 @@ import {MostVisitedBrowserProxy} from 'chrome://resources/cr_components/most_vis
 import {MostVisitedElement} from 'chrome://resources/cr_components/most_visited/most_visited.js';
 import {MostVisitedPageCallbackRouter, MostVisitedPageHandlerRemote, MostVisitedPageRemote} from 'chrome://resources/cr_components/most_visited/most_visited.mojom-webui.js';
 import {TextDirection} from 'chrome://resources/mojo/mojo/public/mojom/base/text_direction.mojom-webui.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {eventToPromise} from 'chrome://webui-test/test_util.js';
 
 import {assertFocus, keydown} from './most_visited_test_support.js';
@@ -47,7 +47,7 @@ suite('CrComponentsMostVisitedFocusTest', () => {
   setup(() => {
     document.body.innerHTML = window.trustedTypes!.emptyHTML;
 
-    const handler = TestBrowserProxy.fromClass(MostVisitedPageHandlerRemote);
+    const handler = TestMock.fromClass(MostVisitedPageHandlerRemote);
     const callbackRouter = new MostVisitedPageCallbackRouter();
     MostVisitedBrowserProxy.setInstance(
         new MostVisitedBrowserProxy(handler, callbackRouter));

chrome/test/data/webui/cr_components/most_visited_test.ts

@@ -11,19 +11,20 @@ import {MostVisitedWindowProxy} from 'chrome://resources/cr_components/most_visi
 import {CrButtonElement} from 'chrome://resources/cr_elements/cr_button/cr_button.js';
 import {CrDialogElement} from 'chrome://resources/cr_elements/cr_dialog/cr_dialog.js';
 import {CrInputElement} from 'chrome://resources/cr_elements/cr_input/cr_input.js';
-import {isMac} from 'chrome://resources/js/platform.js';
 import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
+import {isMac} from 'chrome://resources/js/platform.js';
 import {TextDirection} from 'chrome://resources/mojo/mojo/public/mojom/base/text_direction.mojom-webui.js';
 import {assertDeepEquals, assertEquals, assertFalse, assertNotEquals, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {flushTasks} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {eventToPromise} from 'chrome://webui-test/test_util.js';
 
 import {$$, assertNotStyle, assertStyle, keydown} from './most_visited_test_support.js';
 
 let mostVisited: MostVisitedElement;
-let windowProxy: MostVisitedWindowProxy&TestBrowserProxy;
-let handler: MostVisitedPageHandlerRemote&TestBrowserProxy;
+let windowProxy: TestMock<MostVisitedWindowProxy>&MostVisitedWindowProxy;
+let handler: TestMock<MostVisitedPageHandlerRemote>&
+    MostVisitedPageHandlerRemote;
 let callbackRouterRemote: MostVisitedPageRemote;
 let mediaListenerWideWidth: FakeMediaQueryList;
 let mediaListenerMediumWidth: FakeMediaQueryList;
@@ -82,7 +83,7 @@ function assertAddShortcutShown() {
 }
 
 function createBrowserProxy() {
-  handler = TestBrowserProxy.fromClass(MostVisitedPageHandlerRemote);
+  handler = TestMock.fromClass(MostVisitedPageHandlerRemote);
   const callbackRouter = new MostVisitedPageCallbackRouter();
   MostVisitedBrowserProxy.setInstance(
       new MostVisitedBrowserProxy(handler, callbackRouter));
@@ -114,7 +115,7 @@ class FakeMediaQueryList extends EventTarget implements MediaQueryList {
 }
 
 function createWindowProxy() {
-  windowProxy = TestBrowserProxy.fromClass(MostVisitedWindowProxy);
+  windowProxy = TestMock.fromClass(MostVisitedWindowProxy);
   windowProxy.setResultMapperFor('matchMedia', (query: string) => {
     const mediaListenerList = new FakeMediaQueryList(query);
     if (query === '(min-width: 672px)') {

chrome/test/data/webui/history/history_clusters/utils.ts

@@ -4,14 +4,15 @@
 
 import {ClusterAction, MetricsProxy, PageCallbackRouter, PageHandlerRemote, RelatedSearchAction, VisitAction, VisitType} from 'chrome://history/history.js';
 import {TestBrowserProxy as BaseTestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 export class TestBrowserProxy extends BaseTestBrowserProxy {
-  handler: PageHandlerRemote&BaseTestBrowserProxy;
+  handler: TestMock<PageHandlerRemote>&PageHandlerRemote;
   callbackRouter: PageCallbackRouter;
 
   constructor() {
     super([]);
-    this.handler = BaseTestBrowserProxy.fromClass(PageHandlerRemote);
+    this.handler = TestMock.fromClass(PageHandlerRemote);
     this.callbackRouter = new PageCallbackRouter();
   }
 }

chrome/test/data/webui/metrics_reporter/metrics_reporter_test.ts

@@ -8,14 +8,14 @@ import {PageMetricsCallbackRouter} from 'chrome://resources/js/metrics_reporter.
 import {BrowserProxyImpl} from 'chrome://resources/js/metrics_reporter/browser_proxy.js';
 import {MetricsReporter, MetricsReporterImpl} from 'chrome://resources/js/metrics_reporter/metrics_reporter.js';
 import {assertEquals, assertFalse, assertTrue} from 'chrome://webui-test/chai_assert.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 suite('MetricsReporterTest', function() {
   const DELTA_TIME: bigint = 1000n;
   let now: bigint;
 
   let callbackRouter: PageMetricsCallbackRouter;
-  const apiProxy = TestBrowserProxy.fromClass(BrowserProxyImpl);
+  const apiProxy = TestMock.fromClass(BrowserProxyImpl);
   let metricsReporter: MetricsReporter;
 
   function forwardTime() {

chrome/test/data/webui/new_tab_page/app_test.ts

@@ -14,19 +14,19 @@ import {PromiseResolver} from 'chrome://resources/js/promise_resolver.js';
 import {assertDeepEquals, assertEquals, assertFalse, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {fakeMetricsPrivate, MetricsTracker} from 'chrome://webui-test/metrics_test_support.js';
 import {flushTasks} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {eventToPromise} from 'chrome://webui-test/test_util.js';
 
 import {assertNotStyle, assertStyle, createBackgroundImage, createTheme, installMock} from './test_support.js';
 
 suite('NewTabPageAppTest', () => {
   let app: AppElement;
-  let windowProxy: TestBrowserProxy<WindowProxy>;
-  let handler: TestBrowserProxy<PageHandlerRemote>;
+  let windowProxy: TestMock<WindowProxy>;
+  let handler: TestMock<PageHandlerRemote>;
   let callbackRouterRemote: PageRemote;
   let metrics: MetricsTracker;
-  let moduleRegistry: TestBrowserProxy<ModuleRegistry>;
-  let backgroundManager: TestBrowserProxy<BackgroundManager>;
+  let moduleRegistry: TestMock<ModuleRegistry>;
+  let backgroundManager: TestMock<BackgroundManager>;
   let moduleResolver: PromiseResolver<Module[]>;
 
   const url: URL = new URL(location.href);

chrome/test/data/webui/new_tab_page/customize_backgrounds_test.ts

@@ -10,7 +10,7 @@ import {NewTabPageProxy, WindowProxy} from 'chrome://new-tab-page/new_tab_page.j
 import {BackgroundCollection, CollectionImage, PageCallbackRouter, PageHandlerRemote} from 'chrome://new-tab-page/new_tab_page.mojom-webui.js';
 import {assertDeepEquals, assertEquals, assertFalse, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {flushTasks} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {eventToPromise, isVisible} from 'chrome://webui-test/test_util.js';
 
 import {assertNotStyle, assertStyle, createBackgroundImage, createTheme, installMock} from './test_support.js';
@@ -22,8 +22,8 @@ function createCollection(
 }
 
 suite('NewTabPageCustomizeBackgroundsTest', () => {
-  let windowProxy: TestBrowserProxy<WindowProxy>;
-  let handler: TestBrowserProxy<PageHandlerRemote>;
+  let windowProxy: TestMock<WindowProxy>;
+  let handler: TestMock<PageHandlerRemote>;
 
   async function createCustomizeBackgrounds():
       Promise<CustomizeBackgroundsElement> {

chrome/test/data/webui/new_tab_page/customize_dialog_test.ts

@@ -10,13 +10,13 @@ import {CustomizeDialogPage, NewTabPageProxy} from 'chrome://new-tab-page/new_ta
 import {PageCallbackRouter, PageHandlerRemote} from 'chrome://new-tab-page/new_tab_page.mojom-webui.js';
 import {assertEquals, assertFalse, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {flushTasks, waitAfterNextRender} from 'chrome://webui-test/polymer_test_util.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 
 import {createBackgroundImage, createTheme, installMock} from './test_support.js';
 
 suite('NewTabPageCustomizeDialogTest', () => {
   let customizeDialog: CustomizeDialogElement;
-  let handler: TestBrowserProxy<PageHandlerRemote>;
+  let handler: TestMock<PageHandlerRemote>;
 
   setup(() => {
     document.body.innerHTML = window.trustedTypes!.emptyHTML;

chrome/test/data/webui/new_tab_page/customize_modules_test.ts

@@ -12,16 +12,16 @@ import {ModuleIdName, PageCallbackRouter, PageHandlerRemote, PageRemote} from 'c
 import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
 import {assertDeepEquals, assertEquals, assertFalse, assertTrue} from 'chrome://webui-test/chai_assert.js';
 import {fakeMetricsPrivate, MetricsTracker} from 'chrome://webui-test/metrics_test_support.js';
-import {TestBrowserProxy} from 'chrome://webui-test/test_browser_proxy.js';
+import {TestMock} from 'chrome://webui-test/test_mock.js';
 import {isVisible} from 'chrome://webui-test/test_util.js';
 
 import {assertNotStyle, assertStyle, installMock} from './test_support.js';
 
 suite('NewTabPageCustomizeModulesTest', () => {
-  let handler: TestBrowserProxy<PageHandlerRemote>;
+  let handler: TestMock<PageHandlerRemote>;
   let callbackRouterRemote: PageRemote;
   let metrics: MetricsTracker;
-  let cartHandler: TestBrowserProxy<CartHandlerRemote>;
+  let cartHandler: TestMock<CartHandlerRemote>;
 
   async function createCustomizeModules(
       allDisabled: boolean,