Move calculation of network conditions for RTT into SDK layer

Rather than living in a panel; it can sit with all the other conditions
and throttling related code in SDK.NetworkManager. I also added some
tests for it.

Bug: 441265851
Change-Id: Ic20b2bc786665a48ed0f76a46d873a7d02847588
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6943175
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Alex Rudenko <alexrudenko@chromium.org>
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
Commit-Queue: Alex Rudenko <alexrudenko@chromium.org>

Author: jackfranklin

front_end/core/sdk/NetworkManager.test.ts

@@ -2193,4 +2193,68 @@ describeWithMockConnection('InterceptedRequest', () => {
     ];
     assert.deepEqual(SDK.NetworkManager.InterceptedRequest.mergeSetCookieHeaders(original, overrides), expected);
   });
+
+  describe('getRecommendedNetworkPreset', () => {
+    it('should recommend "Slow 3G" for high RTT', () => {
+      // RTT >= 276ms should be Slow 3G.
+      const rtt = 500;
+      const preset = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
+      assert.isNotNull(preset);
+      assert.strictEqual(preset?.key, SDK.NetworkManager.Slow3GConditions.key);
+    });
+
+    it('should recommend "Slow 4G" for medium RTT', () => {
+      // RTT between 106ms and 275ms should be Slow 4G.
+      const rtt = 200;
+      const preset = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
+      assert.isNotNull(preset);
+      assert.strictEqual(preset?.key, SDK.NetworkManager.Slow4GConditions.key);
+    });
+
+    it('should recommend "Fast 4G" for low RTT', () => {
+      // RTT between 60ms and 105ms should be Fast 4G.
+      const rtt = 100;
+      const preset = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
+      assert.isNotNull(preset);
+      assert.strictEqual(preset?.key, SDK.NetworkManager.Fast4GConditions.key);
+    });
+
+    it('should return null for very low RTT, suggesting no throttling', () => {
+      // RTT below 60ms should suggest no throttling by returning null.
+      const rtt = 20;
+      const preset = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
+      assert.isNull(preset);
+    });
+
+    it('should handle boundary conditions correctly', () => {
+      // Crossover between Slow 3G and Slow 4G
+      const slow3GPreset = SDK.NetworkManager.getRecommendedNetworkPreset(276);
+      assert.isNotNull(slow3GPreset);
+      assert.strictEqual(slow3GPreset.key, SDK.NetworkManager.Slow3GConditions.key, 'RTT 276 should be Slow 3G');
+
+      const slow4GAt3GBoundary = SDK.NetworkManager.getRecommendedNetworkPreset(275);
+      assert.isNotNull(slow4GAt3GBoundary);
+      assert.strictEqual(slow4GAt3GBoundary.key, SDK.NetworkManager.Slow4GConditions.key, 'RTT 275 should be Slow 4G');
+
+      // Crossover between Slow 4G and Fast 4G
+      const slow4GAtFast4GBoundary = SDK.NetworkManager.getRecommendedNetworkPreset(106);
+      assert.isNotNull(slow4GAtFast4GBoundary);
+      assert.strictEqual(
+          slow4GAtFast4GBoundary.key, SDK.NetworkManager.Slow4GConditions.key, 'RTT 106 should be Slow 4G');
+
+      const fast4GAtSlow4GBoundary = SDK.NetworkManager.getRecommendedNetworkPreset(105);
+      assert.isNotNull(fast4GAtSlow4GBoundary);
+      assert.strictEqual(
+          fast4GAtSlow4GBoundary.key, SDK.NetworkManager.Fast4GConditions.key, 'RTT 105 should be Fast 4G');
+
+      // Boundary for Fast 4G and No Throttling
+      const fast4GAtNoThrottlingBoundary = SDK.NetworkManager.getRecommendedNetworkPreset(60);
+      assert.isNotNull(fast4GAtNoThrottlingBoundary);
+      assert.strictEqual(
+          fast4GAtNoThrottlingBoundary.key, SDK.NetworkManager.Fast4GConditions.key, 'RTT 60 should be Fast 4G');
+
+      const noThrottlingPreset = SDK.NetworkManager.getRecommendedNetworkPreset(59);
+      assert.isNull(noThrottlingPreset, 'RTT 59 should be null');
+    });
+  });
 });

front_end/core/sdk/NetworkManager.ts

@@ -2413,3 +2413,50 @@ export interface RequestUpdateDroppedEventData {
   mimeType: string;
   lastModified: Date|null;
 }
+
+/**
+ * For the given Round Trip Time (in MilliSeconds), return the best throttling conditions.
+ */
+export function getRecommendedNetworkPreset(rtt: number): Conditions|null {
+  const RTT_COMPARISON_THRESHOLD = 200;
+  const RTT_MINIMUM = 60;
+
+  if (!Number.isFinite(rtt)) {
+    return null;
+  }
+
+  if (rtt < RTT_MINIMUM) {
+    return null;
+  }
+
+  // We pick from the set of presets in the panel but do not want to allow
+  // the "No Throttling" option to be picked.
+  const presets = THROTTLING_CONDITIONS_LOOKUP.values()
+                      .filter(condition => {
+                        return condition !== NoThrottlingConditions;
+                      })
+                      .toArray();
+
+  let closestPreset: Conditions|null = null;
+  let smallestDiff = Infinity;
+  for (const preset of presets) {
+    const {targetLatency} = preset;
+    if (!targetLatency) {
+      continue;
+    }
+
+    const diff = Math.abs(targetLatency - rtt);
+    if (diff > RTT_COMPARISON_THRESHOLD) {
+      continue;
+    }
+
+    if (smallestDiff < diff) {
+      continue;
+    }
+
+    closestPreset = preset;
+    smallestDiff = diff;
+  }
+
+  return closestPreset;
+}

front_end/panels/mobile_throttling/ThrottlingPresets.ts

@@ -135,42 +135,6 @@ export class ThrottlingPresets {
     ];
   }
 
-  static getRecommendedNetworkPreset(rtt: number): SDK.NetworkManager.Conditions|null {
-    const RTT_COMPARISON_THRESHOLD = 200;
-    const RTT_MINIMUM = 60;
-
-    if (!Number.isFinite(rtt)) {
-      return null;
-    }
-
-    if (rtt < RTT_MINIMUM) {
-      return null;
-    }
-
-    let closestPreset: SDK.NetworkManager.Conditions|null = null;
-    let smallestDiff = Infinity;
-    for (const preset of ThrottlingPresets.networkPresets) {
-      const {targetLatency} = preset;
-      if (!targetLatency) {
-        continue;
-      }
-
-      const diff = Math.abs(targetLatency - rtt);
-      if (diff > RTT_COMPARISON_THRESHOLD) {
-        continue;
-      }
-
-      if (smallestDiff < diff) {
-        continue;
-      }
-
-      closestPreset = preset;
-      smallestDiff = diff;
-    }
-
-    return closestPreset;
-  }
-
   static networkPresets: SDK.NetworkManager.Conditions[] = [
     SDK.NetworkManager.Fast4GConditions,
     SDK.NetworkManager.Slow4GConditions,

front_end/panels/timeline/components/LiveMetricsView.ts

@@ -14,6 +14,7 @@ import './MetricCard.js';
 import * as Common from '../../../core/common/common.js';
 import * as i18n from '../../../core/i18n/i18n.js';
 import type * as Platform from '../../../core/platform/platform.js';
+import * as SDK from '../../../core/sdk/sdk.js';
 import * as CrUXManager from '../../../models/crux-manager/crux-manager.js';
 import * as EmulationModel from '../../../models/emulation/emulation.js';
 import * as LiveMetrics from '../../../models/live-metrics/live-metrics.js';
@@ -27,7 +28,6 @@ import type * as Settings from '../../../ui/components/settings/settings.js';
 import * as UI from '../../../ui/legacy/legacy.js';
 import * as Lit from '../../../ui/lit/lit.js';
 import * as VisualLogging from '../../../ui/visual_logging/visual_logging.js';
-import * as MobileThrottling from '../../mobile_throttling/mobile_throttling.js';
 import {getThrottlingRecommendations} from '../utils/Helpers.js';
 
 import {md} from './insights/Helpers.js';
@@ -589,7 +589,7 @@ export class LiveMetricsView extends LegacyWrapper.LegacyWrapper.WrappableCompon
       return i18nString(UIStrings.tryDisablingThrottling);
     }
 
-    const conditions = MobileThrottling.ThrottlingPresets.ThrottlingPresets.getRecommendedNetworkPreset(rtt);
+    const conditions = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
     if (!conditions) {
       return null;
     }

front_end/panels/timeline/utils/Helpers.ts

@@ -6,7 +6,6 @@ import * as Platform from '../../../core/platform/platform.js';
 import * as SDK from '../../../core/sdk/sdk.js';
 import * as CrUXManager from '../../../models/crux-manager/crux-manager.js';
 import type * as Trace from '../../../models/trace/trace.js';
-import * as MobileThrottling from '../../mobile_throttling/mobile_throttling.js';
 
 const MAX_ORIGIN_LENGTH = 60;
 
@@ -24,7 +23,7 @@ export function getThrottlingRecommendations(): {
   const response = CrUXManager.CrUXManager.instance().getSelectedFieldMetricData('round_trip_time');
   if (response?.percentiles) {
     const rtt = Number(response.percentiles.p75);
-    networkConditions = MobileThrottling.ThrottlingPresets.ThrottlingPresets.getRecommendedNetworkPreset(rtt);
+    networkConditions = SDK.NetworkManager.getRecommendedNetworkPreset(rtt);
   }
 
   return {