tests: simplify serving of zone.js (#9672)

lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html

@@ -418,12 +418,14 @@ <h2>Do better web tester page</h2>
 }
 </script>
 
-<!-- PASS: not in header, so it does not block rendering. zone.js is loaded
-     by the static-server and provides a polyfill for Promise. -->
-<script src="/zone.js"></script>
+<!-- Including this script validates that driver.evaluateAsync() still works even with
+  window.Promise being mucked with. See file source for details.
+  Also, script is located down here to avoid being flagged in render-blocking-resources. -->
+<script src="./third_party/aggressive-promise-polyfill.js"></script>
+
 <!-- FAIL(is-on-https): requires a non-localhost http file
-     FAIL: Loads a vulnerable JS library
--->
+     FAIL(no-vulnerable-libraries): Loads a vulnerable JS library -->
 <script src="http://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
+
 </body>
 </html>

lighthouse-cli/test/fixtures/static-server.js

@@ -47,19 +47,13 @@ function requestHandler(request, response) {
     absoluteFilePath = path.join(__dirname, '/../../../', filePath);
   }
 
-  if (filePath === '/zone.js') {
-    // evaluateAsync previously had a bug that LH would fail if a page polyfilled Promise.
-    // We bring in an aggressive Promise polyfill (zone) to ensure we don't still fail.
-    const zonePath = '../../../node_modules/zone.js';
-    absoluteFilePath = path.join(__dirname, `${zonePath}/dist/zone.js`);
-  } else {
-    // Otherwise, disallow file requests outside of LH folder
-    const filePathDir = path.parse(absoluteFilePath).dir;
-    if (!filePathDir.startsWith(lhRootDirPath)) {
-      return readFileCallback(new Error('Disallowed path'));
-    }
+  // Disallow file requests outside of LH folder
+  const filePathDir = path.parse(absoluteFilePath).dir;
+  if (!filePathDir.startsWith(lhRootDirPath)) {
+    return readFileCallback(new Error('Disallowed path'));
   }
 
+  // Check if the file exists, then read it and serve it.
   fs.exists(absoluteFilePath, fsExistsCallback);
 
   function fsExistsCallback(fileExists) {

package.json

@@ -127,8 +127,7 @@
     "pretty-json-stringify": "^0.0.2",
     "puppeteer": "^1.19.0",
     "terser": "^4.2.0",
-    "typescript": "3.5.3",
-    "zone.js": "^0.7.3"
+    "typescript": "3.5.3"
   },
   "dependencies": {
     "axe-core": "3.3.0",

yarn.lock

@@ -7964,8 +7964,3 @@ zip-stream@^2.0.1:
     archiver-utils "^2.0.0"
     compress-commons "^1.2.0"
     readable-stream "^2.0.0"
-
-zone.js@^0.7.3:
-  version "0.7.3"
-  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.7.3.tgz#d91432b6584f73c2c9e03ce4bb0870becc45d445"
-  integrity sha1-2RQytlhPc8LJ4DzkuwhwvsxF1EU=