core(third-party-summary): check main domain against all third party domains

lighthouse-core/audits/third-party-summary.js

@@ -11,6 +11,7 @@ const Audit = require('./audit.js');
 const BootupTime = require('./bootup-time.js');
 const i18n = require('../lib/i18n/i18n.js');
 const NetworkRecords = require('../computed/network-records.js');
+const MainResource = require('../computed/main-resource.js');
 const MainThreadTasks = require('../computed/main-thread-tasks.js');
 
 const UIStrings = {
@@ -48,7 +49,7 @@ class ThirdPartySummary extends Audit {
       title: str_(UIStrings.title),
       failureTitle: str_(UIStrings.failureTitle),
       description: str_(UIStrings.description),
-      requiredArtifacts: ['traces', 'devtoolsLogs'],
+      requiredArtifacts: ['traces', 'devtoolsLogs', 'URL'],
     };
   }
 
@@ -119,6 +120,8 @@ class ThirdPartySummary extends Audit {
     const trace = artifacts.traces[Audit.DEFAULT_PASS];
     const devtoolsLog = artifacts.devtoolsLogs[Audit.DEFAULT_PASS];
     const networkRecords = await NetworkRecords.request(devtoolsLog, context);
+    const mainResource = await MainResource.request({devtoolsLog, URL: artifacts.URL}, context);
+    const mainEntity = ThirdPartySummary.getEntitySafe(mainResource.url);
     const tasks = await MainThreadTasks.request(trace, context);
     const multiplier = settings.throttlingMethod === 'simulate' ?
       settings.throttling.cpuSlowdownMultiplier : 1;
@@ -128,6 +131,9 @@ class ThirdPartySummary extends Audit {
     const summary = {wastedBytes: 0, wastedMs: 0};
 
     const results = Array.from(summaryByEntity.entries())
+      // Don't consider the page we're on to be third-party.
+      // e.g. Facebook SDK isn't a third-party script on facebook.com
+      .filter(([entity]) => !(mainEntity && mainEntity.name === entity.name))
       .map(([entity, stats]) => {
         summary.wastedBytes += stats.transferSize;
         summary.wastedMs += stats.blockingTime;

lighthouse-core/test/audits/third-party-summary-test.js

@@ -18,6 +18,7 @@ describe('Third party summary', () => {
     const artifacts = {
       devtoolsLogs: {defaultPass: pwaDevtoolsLog},
       traces: {defaultPass: pwaTrace},
+      URL: {finalUrl: 'https://pwa-rocks.com'},
     };
 
     const results = await ThirdPartySummary.audit(artifacts, {computedCache: new Map()});
@@ -54,6 +55,7 @@ describe('Third party summary', () => {
     const artifacts = {
       devtoolsLogs: {defaultPass: pwaDevtoolsLog},
       traces: {defaultPass: pwaTrace},
+      URL: {finalUrl: 'https://pwa-rocks.com'},
     };
 
     const settings = {throttlingMethod: 'simulate', throttling: {cpuSlowdownMultiplier: 4}};
@@ -71,6 +73,7 @@ describe('Third party summary', () => {
     const artifacts = {
       devtoolsLogs: {defaultPass: networkRecordsToDevtoolsLog([{url: 'chrome://version'}])},
       traces: {defaultPass: noThirdPartyTrace},
+      URL: {finalUrl: 'chrome://version'},
     };
 
     const settings = {throttlingMethod: 'simulate', throttling: {cpuSlowdownMultiplier: 4}};
@@ -81,4 +84,37 @@ describe('Third party summary', () => {
       notApplicable: true,
     });
   });
+
+  it('does not return third party entity that matches main resource entity', async () => {
+    const externalArtifacts = {
+      devtoolsLogs: {
+        defaultPass: networkRecordsToDevtoolsLog([
+          {url: 'http://example.com'},
+          {url: 'http://photos-c.ak.fbcdn.net/photos-ak-sf2p/photo.jpg'},
+        ]),
+      },
+      traces: {defaultPass: pwaTrace},
+      URL: {finalUrl: 'http://example.com'},
+    };
+    const facebookArtifacts = {
+      devtoolsLogs: {
+        defaultPass: networkRecordsToDevtoolsLog([
+          {url: 'http://facebook.com'},
+          {url: 'http://photos-c.ak.fbcdn.net/photos-ak-sf2p/photo.jpg'},
+        ]),
+      },
+      traces: {defaultPass: pwaTrace},
+      URL: {finalUrl: 'http://facebook.com'},
+    };
+    const context = {computedCache: new Map()};
+
+    const resultsOnExternal = await ThirdPartySummary.audit(externalArtifacts, context);
+    const resultsOnFacebook = await ThirdPartySummary.audit(facebookArtifacts, context);
+
+    const externalEntities = resultsOnExternal.details.items.map(item => item.entity.text);
+    const facebookEntities = resultsOnFacebook.details.items.map(item => item.entity.text);
+
+    expect(externalEntities).toEqual(['Google Tag Manager', 'Facebook', 'Google Analytics']);
+    expect(facebookEntities).toEqual(['Google Tag Manager', 'Google Analytics']);
+  });
 });