core: remove fonts gatherer

lighthouse-cli/test/cli/__snapshots__/index-test.js.snap

@@ -1104,9 +1104,6 @@ Object {
         Object {
           "path": "seo/robots-txt",
         },
-        Object {
-          "path": "fonts",
-        },
       ],
       "networkQuietThresholdMs": 1000,
       "passName": "defaultPass",

lighthouse-core/audits/font-display.js

@@ -6,8 +6,10 @@
 'use strict';
 
 const Audit = require('./audit');
-const NetworkRequest = require('../lib/network-request');
-const allowedFontFaceDisplays = ['block', 'fallback', 'optional', 'swap'];
+const URL = require('../lib/url-shim').URL;
+const PASSING_FONT_DISPLAY_REGEX = /block|fallback|optional|swap/;
+const CSS_URL_REGEX = /url\((.*?)\)/;
+const CSS_URL_GLOBAL_REGEX = new RegExp(CSS_URL_REGEX, 'g');
 const i18n = require('../lib/i18n/i18n.js');
 
 const UIStrings = {
@@ -16,7 +18,8 @@ const UIStrings = {
   /** Title of a diagnostic audit that provides detail on the load of the page's webfonts. Often the text is invisible for seconds before the webfont resource is loaded. This imperative title is shown to users when there is a significant amount of execution time that could be reduced. */
   failureTitle: 'Ensure text remains visible during webfont load',
   /** Description of a Lighthouse audit that tells the user *why* they should use the font-display CSS feature. This is displayed after a user expands the section to see more. No character length limits. 'Learn More' becomes link text to additional documentation. */
-  description: 'Leverage the font-display CSS feature to ensure text is user-visible while ' +
+  description:
+    'Leverage the font-display CSS feature to ensure text is user-visible while ' +
     'webfonts are loading. ' +
     '[Learn more](https://developers.google.com/web/updates/2016/02/font-display).',
 };
@@ -33,59 +36,91 @@ class FontDisplay extends Audit {
       title: str_(UIStrings.title),
       failureTitle: str_(UIStrings.failureTitle),
       description: str_(UIStrings.description),
-      requiredArtifacts: ['devtoolsLogs', 'Fonts'],
+      requiredArtifacts: ['devtoolsLogs', 'CSSUsage', 'URL'],
     };
   }
 
+  /**
+   *
+   * @param {LH.Artifacts} artifacts
+   */
+  static findPassingFontDisplayDeclarations(artifacts) {
+    /** @type {Set<string>} */
+    const passingURLs = new Set();
+
+    for (const stylesheet of artifacts.CSSUsage.stylesheets) {
+      const newlinesStripped = stylesheet.content.replace(/\n/g, ' ');
+      const fontFaceDeclarations = newlinesStripped.match(/@font-face\s*{(.*?)}/g) || [];
+      for (const declaration of fontFaceDeclarations) {
+        const rawFontDisplay = declaration.match(/font-display:(.*?);/);
+        if (!rawFontDisplay) continue;
+        const hasPassingFontDisplay = PASSING_FONT_DISPLAY_REGEX.test(rawFontDisplay[0]);
+        if (!hasPassingFontDisplay) continue;
+
+        const rawFontURLs = declaration.match(CSS_URL_GLOBAL_REGEX);
+        if (!rawFontURLs) continue;
+
+        const relativeURLs = rawFontURLs
+          // @ts-ignore - guaranteed to match from previous regex, pull URL group out
+          .map(s => s.match(CSS_URL_REGEX)[1].trim())
+          // remove any optional quotes before/after
+          .map(s => {
+            const firstChar = s.charAt(0);
+            if (firstChar === s.charAt(s.length - 1) && (firstChar === '"' || firstChar === '\'')) {
+              return s.substr(1, s.length - 2);
+            }
+
+            return s;
+          });
+
+        const absoluteURLs = relativeURLs.map(url => new URL(url, artifacts.URL.finalUrl));
+
+        for (const url of absoluteURLs) {
+          passingURLs.add(url.href);
+        }
+      }
+    }
+
+    return passingURLs;
+  }
+
   /**
    * @param {LH.Artifacts} artifacts
    * @return {Promise<LH.Audit.Product>}
    */
-  static audit(artifacts) {
+  static async audit(artifacts) {
     const devtoolsLogs = artifacts.devtoolsLogs[this.DEFAULT_PASS];
-    const fontFaces = artifacts.Fonts;
-
-    // Filter font-faces that do not have a display tag with optional or swap
-    const fontsWithoutProperDisplay = fontFaces.filter(fontFace =>
-      !fontFace.display || !allowedFontFaceDisplays.includes(fontFace.display)
-    );
-
-    return artifacts.requestNetworkRecords(devtoolsLogs).then((networkRecords) => {
-      const results = networkRecords.filter(record => {
-        const isFont = record.resourceType === NetworkRequest.TYPES.Font;
-
-        return isFont;
-      })
-        .filter(fontRecord => {
-          // find the fontRecord of a font
-          return !!fontsWithoutProperDisplay.find(fontFace => {
-            return !!fontFace.src && !!fontFace.src.find(src => fontRecord.url === src);
-          });
-        })
-        // calculate wasted time
-        .map(record => {
-          // In reality the end time should be calculated with paint time included
-          // all browsers wait 3000ms to block text so we make sure 3000 is our max wasted time
-          const wastedMs = Math.min((record.endTime - record.startTime) * 1000, 3000);
-
-          return {
-            url: record.url,
-            wastedMs,
-          };
-        });
-
-      const headings = [
-        {key: 'url', itemType: 'url', text: str_(i18n.UIStrings.columnURL)},
-        {key: 'wastedMs', itemType: 'ms', text: str_(i18n.UIStrings.columnWastedMs)},
-      ];
-      const details = Audit.makeTableDetails(headings, results);
-
-      return {
-        score: Number(results.length === 0),
-        rawValue: results.length === 0,
-        details,
-      };
-    });
+    const networkRecords = await artifacts.requestNetworkRecords(devtoolsLogs);
+    const passingFontURLs = FontDisplay.findPassingFontDisplayDeclarations(artifacts);
+
+    const results = networkRecords
+      // Find all fonts...
+      .filter(record => record.resourceType === 'Font')
+      // ...that don't have a passing font-display value
+      .filter(record => !passingFontURLs.has(record.url))
+      .map(record => {
+        // In reality the end time should be calculated with paint time included
+        // all browsers wait 3000ms to block text so we make sure 3000 is our max wasted time
+        const wastedMs = Math.min((record.endTime - record.startTime) * 1000, 3000);
+
+        return {
+          url: record.url,
+          wastedMs,
+        };
+      });
+
+    const headings = [
+      {key: 'url', itemType: 'url', text: str_(i18n.UIStrings.columnURL)},
+      {key: 'wastedMs', itemType: 'ms', text: str_(i18n.UIStrings.columnWastedMs)},
+    ];
+
+    const details = Audit.makeTableDetails(headings, results);
+
+    return {
+      score: Number(results.length === 0),
+      rawValue: results.length === 0,
+      details,
+    };
   }
 }
 

lighthouse-core/config/default-config.js

@@ -74,7 +74,6 @@ const defaultConfig = {
       'seo/embedded-content',
       'seo/canonical',
       'seo/robots-txt',
-      'fonts',
     ],
   },
   {