JS type-check chrome/test/data/webui/test_api.js .

This is needed to allow JS tests themselves to be compiled to ease
future maintenance. js2gtest.js also needs to be compiled for that,
which will be done in a follow-up.

Hand-crafted externs are added for mock4js since it is not able to
be consumed by the compiler directly.

axs_testing.js is precompiled and also not easily consumed by the
compiler, so appropriate suppressions are added to the a11y methods
of test_api.js that deal with it.

Bug: 1000989
Change-Id: Ife6b7595674ffc79c2eadc5484d0804830a648ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1787477
Commit-Queue: Trent Apted <tapted@chromium.org>
Reviewed-by: Dan Beam <dbeam@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713357}

BUILD.gn

@@ -1308,6 +1308,7 @@ if (closure_compile) {
     testonly = true
     data_deps = [
       "chrome/browser/resources:closure_compile",
+      "chrome/test:closure_compile",
       "components/neterror/resources:closure_compile",
       "components/security_interstitials/core/common/resources:closure_compile",
       "components/sync/driver/resources:closure_compile",

chrome/test/BUILD.gn

@@ -6585,3 +6585,12 @@ if (is_win) {
     ]
   }
 }
+
+group("closure_compile") {
+  testonly = true
+
+  deps = [
+    "data:closure_compile",
+    # TODO(crbug/1000989): Add a dep for base/js2gtest.js.
+  ]
+}

chrome/test/data/BUILD.gn

@@ -4,6 +4,7 @@
 
 import("//chrome/common/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
+import("//third_party/closure_compiler/compile_js.gni")
 import("//tools/grit/grit_rule.gni")
 
 grit("webui_test_resources") {
@@ -30,3 +31,23 @@ mojom("web_ui_test_bindings") {
     "webui/web_ui_test.mojom",
   ]
 }
+
+js_type_check("closure_compile") {
+  deps = [
+    ":test_api_js",
+  ]
+}
+
+js_library("test_api_js") {
+  sources = [
+    "webui/test_api.js",
+  ]
+  externs_list = [
+    "webui/mock4js_externs.js",
+    "//third_party/chaijs/externs/chai-3.5.js",
+    "//ui/webui/resources/js/dom_automation_controller.js",
+  ]
+  deps = [
+    ":web_ui_test_bindings_js_library_for_compile",
+  ]
+}

chrome/test/data/webui/mock4js_externs.js

+// Copyright 2019 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.
+
+/**
+ * @fileoverview
+ * Limited externs used by webui testing from http://mock4js.sourceforge.net/.
+ * Mock4JS is not closure-annotated and unmaintained.
+ * TODO(crbug/844820): Eliminate/replace usage of mock4js and delete this file.
+ */
+
+function mock(klass) {}
+
+const Mock4JS = {
+  verifyAllMocks: function() {},
+  addMockSupport: function(exports) {},
+};
+
+class Mock {
+  proxy() {}
+  expects(expectedCallCount) {}
+  stubs() {}
+  verify() {}
+}

third_party/chaijs/README.chromium

@@ -16,3 +16,5 @@ Local Modifications:
  - Copied license text out of README.md.
  - Externs file from
 https://github.com/google/closure-compiler/tree/master/contrib/externs
+ - Add mising assert.notStrictEqual
+ - Add missing export of chai.expect

third_party/chaijs/externs/chai-3.5.js

@@ -310,6 +310,13 @@ assert.equal = function(actual, expected, opt_message) {};
  */
 assert.strictEqual = function(actual, expected, opt_message) {};
 
+/**
+ * @param {*} actual
+ * @param {*} expected
+ * @param {string=} opt_message
+ */
+assert.notStrictEqual = function(actual, expected, opt_message) {};
+
 /**
  * @param {*} actual
  * @param {*} expected
@@ -535,6 +542,9 @@ chai.Assertion.prototype.assert = function(
 /** @const */
 chai.assert = assert;
 
+/** @const */
+chai.expect = expect;
+
 /** @const */
 chai.util = {};