DevTools: Add axe test for call stack pane

This CL adds an axe accessibility test for the call stack pane. It was
previously reviewed in [1] but was split out because the CL was unwieldy
and it isn't dependent on those changes.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1690089/

Bug: 963183
Change-Id: I247a5e6dfc6a5331c67944e6b95a34f7b06b2e6d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1716213
Commit-Queue: Jack Lynch <jalyn@microsoft.com>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704429}

third_party/blink/web_tests/http/tests/devtools/a11y-axe-core/sources/call-stack-a11y-test-expected.txt

+Testing accessibility in the call stack sidebar pane.
+Set timer for test function.
+Call stack pane content: Show blackboxed framesNot paused(anonymous)test.js:20callWithAsyncStacktest.js:13call1wrapper.js:1Promise.then (async)callWithAsyncStacktest.js:17call2VM wrapper.js:1Promise.then (async)callWithAsyncStacktest.js:17call3VM wrapper.js:1Promise.then (async)callWithAsyncStacktest.js:17call4VM wrapper.js:1Promise.then (async)callWithAsyncStacktest.js:17call5VM wrapper.js:1Promise.then (async)callWithAsyncStacktest.js:17testFunctiontest.js:20setTimeout (async)scheduleTestFunctionVM:3(anonymous)VM:1Show more
+Running the axe-core linter on the call stack sidebar pane.
+aXe violations: []
+
+

third_party/blink/web_tests/http/tests/devtools/a11y-axe-core/sources/call-stack-a11y-test.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.
+
+(async function() {
+  await TestRunner.loadModule('axe_core_test_runner');
+  await TestRunner.loadModule('sources_test_runner');
+  await TestRunner.showPanel('sources');
+
+  TestRunner.addResult('Testing accessibility in the call stack sidebar pane.');
+  await TestRunner.evaluateInPagePromise(`
+      function callWithAsyncStack(f, depth) {
+        if (depth === 0) {
+          f();
+          return;
+        }
+        wrapper = eval('(function call' + depth + '() { callWithAsyncStack(f, depth - 1) }) //# sourceURL=wrapper.js');
+        Promise.resolve().then(wrapper);
+      }
+      function testFunction() {
+        callWithAsyncStack(() => {debugger}, 5);
+      }
+      //# sourceURL=test.js
+    `);
+
+  await SourcesTestRunner.startDebuggerTestPromise(/* quiet */ true);
+  await SourcesTestRunner.runTestFunctionAndWaitUntilPausedPromise();
+  await TestRunner.addSnifferPromise(
+      Sources.CallStackSidebarPane.prototype, '_updatedForTest');
+
+  const callStackPane = runtime.sharedInstance(Sources.CallStackSidebarPane);
+  const callStackElement = callStackPane.contentElement;
+  TestRunner.addResult(`Call stack pane content: ${TestRunner.clearSpecificInfoFromStackFrames(callStackElement.deepTextContent())}`);
+  TestRunner.addResult('Running the axe-core linter on the call stack sidebar pane.');
+  await AxeCoreTestRunner.runValidation(callStackElement);
+
+  TestRunner.completeTest();
+})();