tests(devtools): dynamically fetch chromium version

third-party/download-content-shell/download-content-shell.js

@@ -23,7 +23,8 @@ function main() {
   fs.mkdirSync(CACHE_PATH, {recursive: true});
   deleteOldContentShells();
 
-  findPreviousUploadedPosition(findMostRecentChromiumCommit())
+  findMostRecentChromiumCommit()
+    .then(findPreviousUploadedPosition)
     .then(onUploadedCommitPosition)
     .catch(onError);
 
@@ -64,13 +65,16 @@ function getPlatform() {
   throw new Error(`Unrecognized platform detected: ${process.platform}`);
 }
 
-function findMostRecentChromiumCommit() {
-  // TODO: this code works only if there is a full chromium checkout present.
-  // const commitMessage = shell('git log --max-count=1 --grep="Cr-Commit-Position"').toString().trim();
-  // const commitPosition = commitMessage.match(/Cr-Commit-Position: refs\/heads\/master@\{#([0-9]+)\}/)[1];
-  // return commitPosition;
-  // TODO: make this dynamic.
-  return '822569';
+async function findMostRecentChromiumCommit() {
+  // Fetch the most recent commit from the GitHub Chromium mirror.
+  const githubUrl = 'https://api.github.com/repos/chromium/chromium/commits/master';
+  // https://docs.github.com/en/rest/overview/resources-in-the-rest-api#user-agent-required
+  const options = {headers: {'User-Agent': 'lighthouse'}};
+  const latestCommit = await utils.fetch(githubUrl, options);
+  const commitMessage = JSON.parse(latestCommit).commit.message;
+  const commitPosition = /Cr-Commit-Position: refs\/heads\/master@\{#([0-9]+)\}/.exec(commitMessage)[1];
+
+  return commitPosition;
 }
 
 function deleteOldContentShells() {

third-party/download-content-shell/utils.js

@@ -11,17 +11,21 @@ const parseURL = require('url').parse;
 const shell = require('child_process').execSync;
 const Stream = require('stream').Transform;
 
-function fetch(url) {
+/**
+ * @param {string} url
+ * @param {import('http').RequestOptions} [options]
+ */
+function fetch(url, options = {}) {
   return new Promise(fetchPromise);
 
   function fetchPromise(resolve, reject) {
     let request;
     const protocol = parseURL(url).protocol;
     const handleResponse = getCallback.bind(null, resolve, reject);
     if (protocol === 'https:') {
-      request = https.get(url, handleResponse);
+      request = https.get(url, options, handleResponse);
     } else if (protocol === 'http:') {
-      request = http.get(url, handleResponse);
+      request = http.get(url, options, handleResponse);
     } else {
       reject(new Error(`Invalid protocol for url: ${url}`));
       return;
@@ -31,7 +35,7 @@ function fetch(url) {
 
   function getCallback(resolve, reject, response) {
     if (response.statusCode !== 200) {
-      reject(new Error(`Request error: + ${response.statusCode}`));
+      reject(new Error(`Request error: ${response.statusCode}`));
       return;
     }
     const body = new Stream();