core(lantern): remove usage of Lighthouse constants module (#16062)

core/config/constants.js

@@ -4,50 +4,9 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/**
- * Adjustments needed for DevTools network throttling to simulate
- * more realistic network conditions.
- * @see https://crbug.com/721112
- * @see https://docs.google.com/document/d/10lfVdS1iDWCRKQXPfbxEn4Or99D64mvNlugP1AQuFlE/edit
- */
-const DEVTOOLS_RTT_ADJUSTMENT_FACTOR = 3.75;
-const DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR = 0.9;
+import * as Lantern from '../lib/lantern/lantern.js';
 
-const throttling = {
-  DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
-  DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
-  // These values align with WebPageTest's definition of "Fast 3G"
-  // But offer similar characteristics to roughly the 75th percentile of 4G connections.
-  mobileSlow4G: {
-    rttMs: 150,
-    throughputKbps: 1.6 * 1024,
-    requestLatencyMs: 150 * DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
-    downloadThroughputKbps: 1.6 * 1024 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
-    uploadThroughputKbps: 750 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
-    cpuSlowdownMultiplier: 4,
-  },
-  // These values partially align with WebPageTest's definition of "Regular 3G".
-  // These values are meant to roughly align with Chrome UX report's 3G definition which are based
-  // on HTTP RTT of 300-1400ms and downlink throughput of <700kbps.
-  mobileRegular3G: {
-    rttMs: 300,
-    throughputKbps: 700,
-    requestLatencyMs: 300 * DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
-    downloadThroughputKbps: 700 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
-    uploadThroughputKbps: 700 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
-    cpuSlowdownMultiplier: 4,
-  },
-  // Using a "broadband" connection type
-  // Corresponds to "Dense 4G 25th percentile" in https://docs.google.com/document/d/1Ft1Bnq9-t4jK5egLSOc28IL4TvR-Tt0se_1faTA4KTY/edit#heading=h.bb7nfy2x9e5v
-  desktopDense4G: {
-    rttMs: 40,
-    throughputKbps: 10 * 1024,
-    cpuSlowdownMultiplier: 1,
-    requestLatencyMs: 0, // 0 means unset
-    downloadThroughputKbps: 0,
-    uploadThroughputKbps: 0,
-  },
-};
+const throttling = Lantern.constants.throttling;
 
 /**
  * @type {Required<LH.SharedFlagsSettings['screenEmulation']>}

core/lib/lantern/lantern.js

@@ -28,6 +28,48 @@ const NetworkRequestTypes = {
   Prefetch: 'Prefetch',
 };
 
+const DEVTOOLS_RTT_ADJUSTMENT_FACTOR = 3.75;
+const DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR = 0.9;
+
+const throttling = {
+  DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
+  DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
+  // These values align with WebPageTest's definition of "Fast 3G"
+  // But offer similar characteristics to roughly the 75th percentile of 4G connections.
+  mobileSlow4G: {
+    rttMs: 150,
+    throughputKbps: 1.6 * 1024,
+    requestLatencyMs: 150 * DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
+    downloadThroughputKbps: 1.6 * 1024 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
+    uploadThroughputKbps: 750 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
+    cpuSlowdownMultiplier: 4,
+  },
+  // These values partially align with WebPageTest's definition of "Regular 3G".
+  // These values are meant to roughly align with Chrome UX report's 3G definition which are based
+  // on HTTP RTT of 300-1400ms and downlink throughput of <700kbps.
+  mobileRegular3G: {
+    rttMs: 300,
+    throughputKbps: 700,
+    requestLatencyMs: 300 * DEVTOOLS_RTT_ADJUSTMENT_FACTOR,
+    downloadThroughputKbps: 700 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
+    uploadThroughputKbps: 700 * DEVTOOLS_THROUGHPUT_ADJUSTMENT_FACTOR,
+    cpuSlowdownMultiplier: 4,
+  },
+  // Using a "broadband" connection type
+  // Corresponds to "Dense 4G 25th percentile" in https://docs.google.com/document/d/1Ft1Bnq9-t4jK5egLSOc28IL4TvR-Tt0se_1faTA4KTY/edit#heading=h.bb7nfy2x9e5v
+  desktopDense4G: {
+    rttMs: 40,
+    throughputKbps: 10 * 1024,
+    cpuSlowdownMultiplier: 1,
+    requestLatencyMs: 0, // 0 means unset
+    downloadThroughputKbps: 0,
+    uploadThroughputKbps: 0,
+  },
+};
+
+const constants = {throttling};
+
 export {
   NetworkRequestTypes,
+  constants,
 };

core/lib/lantern/simulator/simulator.js

@@ -10,9 +10,9 @@ import {TcpConnection} from './tcp-connection.js';
 import {ConnectionPool} from './connection-pool.js';
 import {DNSCache} from './dns-cache.js';
 import {SimulatorTimingMap} from './simulator-timing-map.js';
-import * as constants from '../../../config/constants.js';
+import {constants} from '../lantern.js';
 
-const mobileSlow4G = constants.throttling.mobileSlow4G;
+const defaultThrottling = constants.throttling.mobileSlow4G;
 
 /** @typedef {import('../base-node.js').Node} Node */
 /** @typedef {import('../network-node.js').NetworkNode} NetworkNode */
@@ -113,10 +113,10 @@ class Simulator {
     /** @type {Required<Lantern.Simulation.Options>} */
     this._options = Object.assign(
       {
-        rtt: mobileSlow4G.rttMs,
-        throughput: mobileSlow4G.throughputKbps * 1024,
+        rtt: defaultThrottling.rttMs,
+        throughput: defaultThrottling.throughputKbps * 1024,
         maximumConcurrentRequests: DEFAULT_MAXIMUM_CONCURRENT_REQUESTS,
-        cpuSlowdownMultiplier: mobileSlow4G.cpuSlowdownMultiplier,
+        cpuSlowdownMultiplier: defaultThrottling.cpuSlowdownMultiplier,
         layoutTaskMultiplier: DEFAULT_LAYOUT_TASK_MULTIPLIER,
         additionalRttByOrigin: new Map(),
         serverResponseTimeByOrigin: new Map(),

core/test/lib/lantern/metrics/speed-index-test.js

@@ -4,11 +4,11 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import * as constants from '../../../../config/constants.js';
 import {readJson} from '../../../test-utils.js';
 import {SpeedIndex} from '../../../../lib/lantern/metrics/speed-index.js';
 import {FirstContentfulPaint} from '../../../../lib/lantern/metrics/first-contentful-paint.js';
 import {getComputationDataFromFixture} from './metric-test-utils.js';
+import {constants} from '../../../../lib/lantern/lantern.js';
 
 const trace = readJson('../../../fixtures/artifacts/progressive-app/trace.json', import.meta);