Add a DEFAULT_TRACE

lighthouse-core/audits/audit.js

@@ -16,7 +16,16 @@
  */
 'use strict';
 
+const DEFAULT_TRACE = 'defaultPass';
+
 class Audit {
+  /**
+   * @return {!String}
+   */
+  static get DEFAULT_TRACE() {
+    return DEFAULT_TRACE;
+  }
+
   /**
    * @return {!AuditMeta}
    */

lighthouse-core/audits/estimated-input-latency.js

@@ -24,7 +24,6 @@ const Formatter = require('../formatters/formatter');
 // https://www.desmos.com/calculator/srv0hqhf7d
 const SCORING_POINT_OF_DIMINISHING_RETURNS = 50;
 const SCORING_MEDIAN = 100;
-const TRACE_NAME = 'firstPass';
 
 class EstimatedInputLatency extends Audit {
   /**
@@ -51,7 +50,8 @@ class EstimatedInputLatency extends Audit {
       // Use speedline's first paint as start of range for input latency check.
       const startTime = artifacts.Speedline.first;
 
-      const trace = artifacts.traces[TRACE_NAME] && artifacts.traces[TRACE_NAME].traceContents;
+      const trace = artifacts.traces[this.DEFAULT_TRACE] &&
+        artifacts.traces[this.DEFAULT_TRACE].traceContents;
       const tracingProcessor = new TracingProcessor();
       const model = tracingProcessor.init(trace);
       const latencyPercentiles = TracingProcessor.getRiskToResponsiveness(model, trace, startTime);

lighthouse-core/audits/first-meaningful-paint.js

@@ -29,8 +29,6 @@ const SCORING_MEDIAN = 4000;
 
 const BLOCK_FIRST_MEANINGFUL_PAINT_IF_BLANK_CHARACTERS_MORE_THAN = 200;
 
-const TRACE_NAME = 'firstPass';
-
 class FirstMeaningfulPaint extends Audit {
   /**
    * @return {!AuditMeta}
@@ -54,7 +52,7 @@ class FirstMeaningfulPaint extends Audit {
    */
   static audit(artifacts) {
     return new Promise((resolve, reject) => {
-      const traceContents = artifacts.traces[TRACE_NAME].traceContents;
+      const traceContents = artifacts.traces[this.DEFAULT_TRACE].traceContents;
       if (!traceContents || !Array.isArray(traceContents)) {
         throw new Error(FAILURE_MESSAGE);
       }

lighthouse-core/audits/user-timings.js

@@ -22,7 +22,6 @@ const Formatter = require('../formatters/formatter');
 const TimelineModel = require('../lib/traces/devtools-timeline-model');
 
 const FAILURE_MESSAGE = 'Trace data not found.';
-const TRACE_NAME = 'firstPass';
 
 /**
  * @param {!Array<!Object>} traceData
@@ -130,7 +129,8 @@ class UserTimings extends Audit {
   static audit(artifacts) {
     return new Promise((resolve, reject) => {
       const traceContents =
-        artifacts.traces[TRACE_NAME] && artifacts.traces[TRACE_NAME].traceContents;
+        artifacts.traces[this.DEFAULT_TRACE] &&
+        artifacts.traces[this.DEFAULT_TRACE].traceContents;
       if (!traceContents || !Array.isArray(traceContents)) {
         throw new Error(FAILURE_MESSAGE);
       }

lighthouse-core/config/default.json

@@ -2,7 +2,6 @@
   "passes": [{
     "network": true,
     "trace": true,
-    "traceName": "firstPass",
     "loadPage": true,
     "gatherers": [
       "url",

lighthouse-core/driver/index.js

@@ -16,8 +16,9 @@
  */
 'use strict';
 
-class Driver {
+const Audit = require('../audits/audit');
 
+class Driver {
   static loadPage(driver, options) {
     // Since a Page.reload command does not let a service worker take over, we
     // navigate away and then come back to reload. We do not `waitForLoad` on
@@ -165,10 +166,7 @@ class Driver {
               .then(_ => this.afterPass(runOptions))
               .then(loadData => {
                 Object.assign(tracingData, loadData);
-
-                if (config.traceName) {
-                  tracingData.traces[config.traceName] = loadData;
-                }
+                tracingData.traces[config.traceName || Audit.DEFAULT_TRACE] = loadData;
               })
               .then(_ => this.tearDown(runOptions));
         }, Promise.resolve());

lighthouse-core/test/audits/estimated-input-latency.js

@@ -24,7 +24,7 @@ const traceContents = require('../fixtures/traces/progressive-app.json');
 describe('Performance: estimated-input-latency audit', () => {
   it('scores a -1 with invalid trace data', () => {
     const output = Audit.audit({
-      traces: {firstPass: {traceContents: '[{"pid": 15256,"tid": 1295,"t'}},
+      traces: {[Audit.DEFAULT_TRACE]: {traceContents: '[{"pid": 15256,"tid": 1295,"t'}},
       Speedline: {
         first: 500
       }
@@ -35,7 +35,7 @@ describe('Performance: estimated-input-latency audit', () => {
 
   it('evaluates valid input correctly', () => {
     const output = Audit.audit({
-      traces: {firstPass: {traceContents}},
+      traces: {[Audit.DEFAULT_TRACE]: {traceContents}},
       Speedline: {
         first: 500
       }

lighthouse-core/test/audits/first-meaningful-paint.js

@@ -38,10 +38,11 @@ describe('Performance: first-meaningful-paint audit', () => {
     it('processes a valid trace file', done => {
       const traceData = require('../fixtures/traces/progressive-app.json');
       assert.doesNotThrow(_ => {
-        Audit.audit({traces: {firstPass: {traceContents: traceData}}}).then(response => {
-          fmpResult = response;
-          done();
-        });
+        Audit.audit({traces: {[Audit.DEFAULT_TRACE]: {traceContents: traceData}}})
+          .then(response => {
+            fmpResult = response;
+            done();
+          });
       });
     });
 

lighthouse-core/test/audits/user-timing.js

@@ -29,7 +29,7 @@ describe('Performance: user-timings audit', () => {
   });
 
   it('evaluates valid input correctly', () => {
-    return Audit.audit({traces: {firstPass: {traceContents}}})
+    return Audit.audit({traces: {[Audit.DEFAULT_TRACE]: {traceContents}}})
       .then(response => {
         assert.equal(response.score, 2);
         assert.ok(!Number.isNaN(response.extendedInfo.value[0].startTime));

lighthouse-core/test/runner.js

@@ -16,6 +16,7 @@
 const Runner = require('../runner');
 const fakeDriver = require('./driver/fake-driver');
 const Config = require('../config');
+const Audit = require('../audits/audit');
 const assert = require('assert');
 const path = require('path');
 
@@ -87,7 +88,7 @@ describe('Runner', () => {
 
       artifacts: {
         traces: {
-          firstPass: {
+          [Audit.DEFAULT_TRACE]: {
             traceContents: path.join(__dirname,
                            '/fixtures/traces/trace-user-timings.json')
           }