core: remove no-mutation-events audit

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

@@ -208,39 +208,6 @@ <h2>Do better web tester page</h2>
   const db = openDatabase('mydb', '1.0', 'my first database', 1024);
 }
 
-function mutationEvenTest() {
-  // FAIL
-  document.addEventListener('DOMNodeInserted', function(e) {
-    console.log('DOMNodeInserted');
-  });
-
-  // FAIL
-  document.addEventListener('DOMNodeRemoved', function(e) {
-    console.log('DOMNodeRemoved');
-  });
-
-  // FAIL
-  document.body.addEventListener('DOMNodeInserted', function(e) {
-    console.log('DOMNodeInserted');
-  });
-
-  // FAIL
-  const el = document.querySelector('#touchmove-section');
-  el.addEventListener('DOMNodeInserted', function(e) {
-    console.log('DOMNodeInserted on element');
-  });
-
-  // FAIL
-  window.addEventListener('DOMNodeInserted', function(e) {
-    console.log('DOMNodeInserted');
-  });
-
-  // PASS - not MutationEvents
-  window.addEventListener('DOMContentLoaded', function(e) {
-    console.log('DOMContentLoaded');
-  });
-}
-
 function passiveEventsListenerTest() {
   // FAIL
   window.addEventListener('wheel', function(e) {
@@ -364,7 +331,6 @@ <h2>Do better web tester page</h2>
   dateNowTest();
   consoleTimeTest();
   websqlTest();
-  mutationEvenTest();
   passiveEventsListenerTest();
   geolocationOnStartTest();
   notificationOnStartTest();
@@ -387,9 +353,6 @@ <h2>Do better web tester page</h2>
   if (params.has('websql')) {
     websqlTest();
   }
-  if (params.has('mutationEvents')) {
-    mutationEvenTest();
-  }
   if (params.has('passiveEvents')) {
     passiveEventsListenerTest();
   }

lighthouse-cli/test/smokehouse/dobetterweb/dbw-expectations.js

@@ -61,14 +61,6 @@ module.exports = [
           },
         },
       },
-      'no-mutation-events': {
-        score: 0,
-        details: {
-          items: {
-            length: 6,
-          },
-        },
-      },
       'no-vulnerable-libraries': {
         score: 0,
         details: {

lighthouse-cli/test/smokehouse/offline-local/offline-expectations.js

@@ -36,9 +36,6 @@ module.exports = [
       'no-document-write': {
         score: 1,
       },
-      'no-mutation-events': {
-        score: 1,
-      },
       'no-websql': {
         score: 1,
       },

lighthouse-core/config/default-config.js

@@ -29,7 +29,6 @@ module.exports = {
       'chrome-console-messages',
       'image-usage',
       'accessibility',
-      'dobetterweb/all-event-listeners',
       'dobetterweb/anchors-with-no-rel-noopener',
       'dobetterweb/appcache',
       'dobetterweb/domstats',
@@ -166,7 +165,6 @@ module.exports = {
     'dobetterweb/external-anchors-use-rel-noopener',
     'dobetterweb/geolocation-on-start',
     'dobetterweb/no-document-write',
-    'dobetterweb/no-mutation-events',
     'dobetterweb/no-vulnerable-libraries',
     'dobetterweb/no-websql',
     'dobetterweb/notification-on-start',
@@ -371,7 +369,6 @@ module.exports = {
         {id: 'is-on-https', weight: 1},
         {id: 'uses-http2', weight: 1},
         {id: 'uses-passive-event-listeners', weight: 1},
-        {id: 'no-mutation-events', weight: 1},
         {id: 'no-document-write', weight: 1},
         {id: 'external-anchors-use-rel-noopener', weight: 1},
         {id: 'geolocation-on-start', weight: 1},

lighthouse-core/gather/driver.js

@@ -1077,38 +1077,6 @@ class Driver {
     await this.evaluteScriptOnNewDocument(scriptStr);
   }
 
-  /**
-   * Keeps track of calls to a JS function and returns a list of {url, line, col}
-   * of the usage. Should be called before page load (in beforePass).
-   * @param {string} funcName The function name to track ('Date.now', 'console.time').
-   * @return {function(): Promise<Array<{url: string, line: number, col: number}>>}
-   *     Call this method when you want results.
-   */
-  captureFunctionCallSites(funcName) {
-    const globalVarToPopulate = `window['__${funcName}StackTraces']`;
-    const collectUsage = () => {
-      return this.evaluateAsync(
-          `Array.from(${globalVarToPopulate}).map(item => JSON.parse(item))`)
-        .then(result => {
-          if (!Array.isArray(result)) {
-            throw new Error(
-                'Driver failure: Expected evaluateAsync results to be an array ' +
-                `but got "${JSON.stringify(result)}" instead.`);
-          }
-          // Filter out usage from extension content scripts.
-          return result.filter(item => !item.isExtension);
-        });
-    };
-
-    const funcBody = pageFunctions.captureJSCallUsage.toString();
-
-    this.evaluteScriptOnNewDocument(`
-        ${globalVarToPopulate} = new Set();
-        (${funcName} = ${funcBody}(${funcName}, ${globalVarToPopulate}))`);
-
-    return collectUsage;
-  }
-
   /**
    * @param {Array<string>} urls URL patterns to block. Wildcards ('*') are allowed.
    * @return {Promise<void>}