chrome-devtools-frontend/front_end/models/timeline_model/TimelineModel.ts

Chrome DevTools UI

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

// TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
/* eslint-disable @typescript-eslint/no-explicit-any */

import * as Common from '../../core/common/common.js';
import * as i18n from '../../core/i18n/i18n.js';
import * as Platform from '../../core/platform/platform.js';
import * as Root from '../../core/root/root.js';
import * as SDK from '../../core/sdk/sdk.js';
import type * as Protocol from '../../generated/protocol.js';

import {TimelineJSProfileProcessor} from './TimelineJSProfile.js';

const UIStrings = {
  /**
  *@description Text for the name of a thread of the page
  *@example {1} PH1
  */
  threadS: 'Thread {PH1}',
  /**
  *@description Text shown when rendering the User Interactions track in the Performance panel
  */
  userInteractions: 'User Interactions',
  /**
  *@description Title of a worker in the timeline flame chart of the Performance panel
  *@example {https://google.com} PH1
  */
  workerS: '`Worker` — {PH1}',
  /**
  *@description Title of a worker in the timeline flame chart of the Performance panel
  */
  dedicatedWorker: 'Dedicated `Worker`',
  /**
  *@description Title of a worker in the timeline flame chart of the Performance panel
  *@example {FormatterWorker} PH1
  *@example {https://google.com} PH2
  */
  workerSS: '`Worker`: {PH1} — {PH2}',

  /**
   *@description Title of a bidder auction worklet with known URL in the timeline flame chart of the Performance panel
   *@example {https://google.com} PH1
   */
  bidderWorkletS: 'Bidder Worklet — {PH1}',

  /**
   *@description Title of a seller auction worklet with known URL in the timeline flame chart of the Performance panel
   *@example {https://google.com} PH1
   */
  sellerWorkletS: 'Seller Worklet — {PH1}',

  /**
   *@description Title of an auction worklet with known URL in the timeline flame chart of the Performance panel
   *@example {https://google.com} PH1
   */
  unknownWorkletS: 'Auction Worklet — {PH1}',

  /**
   *@description Title of a bidder auction worklet in the timeline flame chart of the Performance panel
   */
  bidderWorklet: 'Bidder Worklet',

  /**
   *@description Title of a seller auction worklet in the timeline flame chart of the Performance panel
   */
  sellerWorklet: 'Seller Worklet',

  /**
   *@description Title of an auction worklet in the timeline flame chart of the Performance panel
   */
  unknownWorklet: 'Auction Worklet',

  /**
   *@description Title of control thread of a service process for an auction worklet in the timeline flame chart of the Performance panel
   */
  workletService: 'Auction Worklet Service',

  /**
   *@description Title of control thread of a service process for an auction worklet with known URL in the timeline flame chart of the Performance panel
   * @example {https://google.com} PH1
   */
  workletServiceS: 'Auction Worklet Service — {PH1}',

};
const str_ = i18n.i18n.registerUIStrings('models/timeline_model/TimelineModel.ts', UIStrings);
const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
export class TimelineModelImpl {
  private isGenericTraceInternal!: boolean;
  private tracksInternal!: Track[];
  private namedTracks!: Map<TrackType, Track>;
  private inspectedTargetEventsInternal!: SDK.TracingModel.Event[];
  private timeMarkerEventsInternal!: SDK.TracingModel.Event[];
  private sessionId!: string|null;
  private mainFrameNodeId!: number|null;
  private pageFrames!: Map<Protocol.Page.FrameId, PageFrame>;
  private auctionWorklets!: Map<string, AuctionWorklet>;
  private cpuProfilesInternal!: SDK.CPUProfileDataModel.CPUProfileDataModel[];
  private workerIdByThread!: WeakMap<SDK.TracingModel.Thread, string>;
  private requestsFromBrowser!: Map<string, SDK.TracingModel.Event>;
  private mainFrame!: PageFrame;
  private minimumRecordTimeInternal: number;
  private maximumRecordTimeInternal: number;
  private totalBlockingTimeInternal: number;
  private estimatedTotalBlockingTime: number;
  private asyncEventTracker!: TimelineAsyncEventTracker;
  private invalidationTracker!: InvalidationTracker;
  private layoutInvalidate!: {
    [x: string]: SDK.TracingModel.Event|null,
  };
  private lastScheduleStyleRecalculation!: {
    [x: string]: SDK.TracingModel.Event,
  };
  private paintImageEventByPixelRefId!: {
    [x: string]: SDK.TracingModel.Event,
  };
  private lastPaintForLayer!: {
    [x: string]: SDK.TracingModel.Event,
  };
  private lastRecalculateStylesEvent!: SDK.TracingModel.Event|null;
  private currentScriptEvent!: SDK.TracingModel.Event|null;
  private eventStack!: SDK.TracingModel.Event[];
  private browserFrameTracking!: boolean;
  private persistentIds!: boolean;
  private legacyCurrentPage!: any;
  private currentTaskLayoutAndRecalcEvents: SDK.TracingModel.Event[];
  private tracingModelInternal: SDK.TracingModel.TracingModel|null;
  private mainFrameLayerTreeId?: any;

  constructor() {
    this.minimumRecordTimeInternal = 0;
    this.maximumRecordTimeInternal = 0;
    this.totalBlockingTimeInternal = 0;
    this.estimatedTotalBlockingTime = 0;

    this.reset();
    this.resetProcessingState();

    this.currentTaskLayoutAndRecalcEvents = [];
    this.tracingModelInternal = null;
  }

  static forEachEvent(
      events: SDK.TracingModel.Event[], onStartEvent: (arg0: SDK.TracingModel.Event) => void,
      onEndEvent: (arg0: SDK.TracingModel.Event) => void,
      onInstantEvent?: ((arg0: SDK.TracingModel.Event, arg1: SDK.TracingModel.Event|null) => void), startTime?: number,
      endTime?: number, filter?: ((arg0: SDK.TracingModel.Event) => boolean)): void {
    startTime = startTime || 0;
    endTime = endTime || Infinity;
    const stack: SDK.TracingModel.Event[] = [];
    const startEvent = TimelineModelImpl.topLevelEventEndingAfter(events, startTime);
    for (let i = startEvent; i < events.length; ++i) {
      const e = events[i];
      if ((e.endTime || e.startTime) < startTime) {
        continue;
      }
      if (e.startTime >= endTime) {
        break;
      }
      if (SDK.TracingModel.TracingModel.isAsyncPhase(e.phase) || SDK.TracingModel.TracingModel.isFlowPhase(e.phase)) {
        continue;
      }
      let last: SDK.TracingModel.Event = stack[stack.length - 1];
      while (last && last.endTime !== undefined && last.endTime <= e.startTime) {
        stack.pop();
        onEndEvent(last);
        last = stack[stack.length - 1];
      }
      if (filter && !filter(e)) {
        continue;
      }
      if (e.duration) {
        onStartEvent(e);
        stack.push(e);
      } else {
        onInstantEvent && onInstantEvent(e, stack[stack.length - 1] || null);
      }
    }
    while (stack.length) {
      const last = stack.pop();
      if (last) {
        onEndEvent(last);
      }
    }
  }

  private static topLevelEventEndingAfter(events: SDK.TracingModel.Event[], time: number): number {
    let index = Platform.ArrayUtilities.upperBound(events, time, (time, event) => time - event.startTime) - 1;
    while (index > 0 && !SDK.TracingModel.TracingModel.isTopLevelEvent(events[index])) {
      index--;
    }
    return Math.max(index, 0);
  }

  isMarkerEvent(event: SDK.TracingModel.Event): boolean {
    switch (event.name) {
      case RecordType.TimeStamp:
        return true;
      case RecordType.MarkFirstPaint:
      case RecordType.MarkFCP:
        return Boolean(this.mainFrame) && event.args.frame === this.mainFrame.frameId && Boolean(event.args.data);
      case RecordType.MarkDOMContent:
      case RecordType.MarkLoad:
      case RecordType.MarkLCPCandidate:
      case RecordType.MarkLCPInvalidate:
        return Boolean(event.args['data']['isOutermostMainFrame'] ?? event.args['data']['isMainFrame']);
      default:
        return false;
    }
  }

  isInteractiveTimeEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.InteractiveTime;
  }

  isLayoutShiftEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.LayoutShift;
  }

  isUserTimingEvent(event: SDK.TracingModel.Event): boolean {
    return event.categoriesString === TimelineModelImpl.Category.UserTiming;
  }

  isEventTimingInteractionEvent(event: SDK.TracingModel.Event): boolean {
    if (event.name !== RecordType.EventTiming) {
      return false;
    }
    type InteractionEventData = {
      duration?: number, interactionId: number,
    };
    const data = event.args.data as InteractionEventData;
    // Filter out:
    // 1. events without a duration, or a duration of 0
    // 2. events without an interactionId, or with an interactionId of 0,
    //    which indicates that it's not a "top level" interaction event and
    //    we can therefore ignore it. This can happen with "mousedown" for
    //    example; an interaction ID is assigned to the "pointerdown" event
    //    as it's the "first" event to be triggered when the user clicks,
    //    but the browser doesn't attempt to assign IDs to all subsequent
    //    events, as that's a hard heuristic to get right.
    const duration = data.duration || 0;
    const interactionId = data.interactionId || 0;
    return (duration > 0 && interactionId > 0);
  }

  isParseHTMLEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.ParseHTML;
  }

  isLCPCandidateEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.MarkLCPCandidate &&
        Boolean(event.args['data']['isOutermostMainFrame'] ?? event.args['data']['isMainFrame']);
  }

  isLCPInvalidateEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.MarkLCPInvalidate &&
        Boolean(event.args['data']['isOutermostMainFrame'] ?? event.args['data']['isMainFrame']);
  }

  isFCPEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.MarkFCP && Boolean(this.mainFrame) &&
        event.args['frame'] === this.mainFrame.frameId;
  }

  isLongRunningTask(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.Task &&
        TimelineData.forEvent(event).warning === TimelineModelImpl.WarningType.LongTask;
  }

  isNavigationStartEvent(event: SDK.TracingModel.Event): boolean {
    return event.name === RecordType.NavigationStart;
  }

  isMainFrameNavigationStartEvent(event: SDK.TracingModel.Event): boolean {
    return this.isNavigationStartEvent(event) &&
        (event.args['data']['isOutermostMainFrame'] ?? event.args['data']['isLoadingMainFrame']) &&
        event.args['data']['documentLoaderURL'];
  }

  static globalEventId(event: SDK.TracingModel.Event, field: string): string {
    const data = event.args['data'] || event.args['beginData'];
    const id = data && data[field];
    if (!id) {
      return '';
    }
    return `${event.thread.process().id()}.${id}`;
  }

  static eventFrameId(event: SDK.TracingModel.Event): Protocol.Page.FrameId|null {
    const data = event.args['data'] || event.args['beginData'];
    return data && data['frame'] || null;
  }

  cpuProfiles(): SDK.CPUProfileDataModel.CPUProfileDataModel[] {
    return this.cpuProfilesInternal;
  }

  totalBlockingTime(): {
    time: number,
    estimated: boolean,
  } {
    if (this.totalBlockingTimeInternal === -1) {
      return {time: this.estimatedTotalBlockingTime, estimated: true};
    }

    return {time: this.totalBlockingTimeInternal, estimated: false};
  }

  targetByEvent(event: SDK.TracingModel.Event): SDK.Target.Target|null {
    // FIXME: Consider returning null for loaded traces.
    const workerId = this.workerIdByThread.get(event.thread);
    const mainTarget = SDK.TargetManager.TargetManager.instance().mainTarget();
    return workerId ? SDK.TargetManager.TargetManager.instance().targetById(workerId) : mainTarget;
  }

  navStartTimes(): Map<string, SDK.TracingModel.Event> {
    if (!this.tracingModelInternal) {
      return new Map();
    }

    return this.tracingModelInternal.navStartTimes();
  }

  setEvents(tracingModel: SDK.TracingModel.TracingModel): void {
    this.reset();
    this.resetProcessingState();
    this.tracingModelInternal = tracingModel;

    this.minimumRecordTimeInternal = tracingModel.minimumRecordTime();
    this.maximumRecordTimeInternal = tracingModel.maximumRecordTime();

    // Remove LayoutShift events from the main thread list of events because they are
    // represented in the experience track. This is done prior to the main thread being processed for its own events.
    const layoutShiftEvents = [];
    for (const process of tracingModel.sortedProcesses()) {
      if (process.name() !== 'Renderer') {
        continue;
      }

      for (const thread of process.sortedThreads()) {
        const shifts = thread.removeEventsByName(RecordType.LayoutShift);
        layoutShiftEvents.push(...shifts);
      }
    }

    this.processSyncBrowserEvents(tracingModel);
    if (this.browserFrameTracking) {
      this.processThreadsForBrowserFrames(tracingModel);
    } else {
      // The next line is for loading legacy traces recorded before M67.
      // TODO(alph): Drop the support at some point.
      const metadataEvents = this.processMetadataEvents(tracingModel);
      this.isGenericTraceInternal = !metadataEvents;
      if (metadataEvents) {
        this.processMetadataAndThreads(tracingModel, metadataEvents);
      } else {
        this.processGenericTrace(tracingModel);
      }
    }
    this.inspectedTargetEventsInternal.sort(SDK.TracingModel.Event.compareStartTime);
    this.processAsyncBrowserEvents(tracingModel);
    this.buildGPUEvents(tracingModel);
    this.buildLoadingEvents(tracingModel, layoutShiftEvents);
    this.collectInteractionEvents(tracingModel);
    this.resetProcessingState();
  }

  private collectInteractionEvents(tracingModel: SDK.TracingModel.TracingModel): void {
    const interactionEvents: SDK.TracingModel.AsyncEvent[] = [];
    for (const process of tracingModel.sortedProcesses()) {
      // Interactions will only appear on the Renderer processes.
      if (process.name() !== 'Renderer') {
        continue;
      }

      // And also only on CrRendererMain threads.
      const rendererThread = process.threadByName('CrRendererMain');
      if (!rendererThread) {
        continue;
      }

      // EventTiming events are async, so we only have to check asyncEvents,
      // and not worry about sync events.
      for (const event of rendererThread.asyncEvents()) {
        if (!this.isEventTimingInteractionEvent(event)) {
          continue;
        }
        interactionEvents.push(event);
      }
    }
    if (interactionEvents.length === 0) {
      // No events found, so bail early and don't bother creating the track
      // because it will be empty.
      return;
    }

    const track = this.ensureNamedTrack(TrackType.UserInteractions);
    track.name = UIStrings.userInteractions;
    track.forMainFrame = true;
    track.asyncEvents = interactionEvents;
  }

  private processGenericTrace(tracingModel: SDK.TracingModel.TracingModel): void {
    let browserMainThread = SDK.TracingModel.TracingModel.browserMainThread(tracingModel);
    if (!browserMainThread && tracingModel.sortedProcesses().length) {
      browserMainThread = tracingModel.sortedProcesses()[0].sortedThreads()[0];
    }
    for (const process of tracingModel.sortedProcesses()) {
      for (const thread of process.sortedThreads()) {
        this.processThreadEvents(
            tracingModel, [{from: 0, to: Infinity}], thread, thread === browserMainThread, false, true,
            WorkletType.NotWorklet, null);
      }
    }
  }

  private processMetadataAndThreads(tracingModel: SDK.TracingModel.TracingModel, metadataEvents: MetadataEvents): void {
    let startTime = 0;
    for (let i = 0, length = metadataEvents.page.length; i < length; i++) {
      const metaEvent = metadataEvents.page[i];
      const process = metaEvent.thread.process();
      const endTime = i + 1 < length ? metadataEvents.page[i + 1].startTime : Infinity;
      if (startTime === endTime) {
        continue;
      }
      this.legacyCurrentPage = metaEvent.args['data'] && metaEvent.args['data']['page'];
      for (const thread of process.sortedThreads()) {
        let workerUrl: Platform.DevToolsPath.UrlString|null = null;
        if (thread.name() === TimelineModelImpl.WorkerThreadName ||
            thread.name() === TimelineModelImpl.WorkerThreadNameLegacy) {
          const workerMetaEvent = metadataEvents.workers.find(e => {
            if (e.args['data']['workerThreadId'] !== thread.id()) {
              return false;
            }
            // This is to support old traces.
            if (e.args['data']['sessionId'] === this.sessionId) {
              return true;
            }
            const frameId = TimelineModelImpl.eventFrameId(e);
            return frameId ? Boolean(this.pageFrames.get(frameId)) : false;
          });
          if (!workerMetaEvent) {
            continue;
          }
          const workerId = workerMetaEvent.args['data']['workerId'];
          if (workerId) {
            this.workerIdByThread.set(thread, workerId);
          }
          workerUrl = workerMetaEvent.args['data']['url'] || Platform.DevToolsPath.EmptyUrlString;
        }
        this.processThreadEvents(
            tracingModel, [{from: startTime, to: endTime}], thread, thread === metaEvent.thread, Boolean(workerUrl),
            true, WorkletType.NotWorklet, workerUrl);
      }
      startTime = endTime;
    }
  }

  private processThreadsForBrowserFrames(tracingModel: SDK.TracingModel.TracingModel): void {
    const processData = new Map<number, {
      from: number,
      to: number,
      main: boolean,
      workletType: WorkletType,
      url: Platform.DevToolsPath.UrlString,
    }[]>();
    for (const frame of this.pageFrames.values()) {
      for (let i = 0; i < frame.processes.length; i++) {
        const pid = frame.processes[i].processId;
        let data = processData.get(pid);
        if (!data) {
          data = [];
          processData.set(pid, data);
        }
        const to = i === frame.processes.length - 1 ? (frame.deletedTime || Infinity) : frame.processes[i + 1].time;
        data.push({
          from: frame.processes[i].time,
          to: to,
          main: !frame.parent,
          url: frame.processes[i].url,
          workletType: WorkletType.NotWorklet,
        });
      }
    }
    for (const auctionWorklet of this.auctionWorklets.values()) {
      const pid = auctionWorklet.processId;
      let data = processData.get(pid);
      if (!data) {
        data = [];
        processData.set(pid, data);
      }
      data.push({
        from: auctionWorklet.startTime,
        to: auctionWorklet.endTime,
        main: false,
        workletType: auctionWorklet.workletType,
        url:
            (auctionWorklet.host ? 'https://' + auctionWorklet.host as Platform.DevToolsPath.UrlString :
                                   Platform.DevToolsPath.EmptyUrlString),
      });
    }
    const allMetadataEvents = tracingModel.devToolsMetadataEvents();
    for (const process of tracingModel.sortedProcesses()) {
      const data = processData.get(process.id());
      if (!data) {
        continue;
      }
      data.sort((a, b) => a.from - b.from || a.to - b.to);
      const ranges = [];
      let lastUrl: Platform.DevToolsPath.UrlString|null = null;
      let lastMainUrl: Platform.DevToolsPath.UrlString|null = null;
      let hasMain = false;
      let allWorklet = true;

      // false: not set, true: inconsistent.
      let workletUrl: Platform.DevToolsPath.UrlString|boolean = false;
      // NotWorklet used for not set.
      let workletType: WorkletType = WorkletType.NotWorklet;
      for (const item of data) {
        const last = ranges[ranges.length - 1];
        if (!last || item.from > last.to) {
          ranges.push({from: item.from, to: item.to});
        } else {
          last.to = item.to;
        }
        if (item.main) {
          hasMain = true;
        }
        if (item.workletType === WorkletType.NotWorklet) {
          allWorklet = false;
        } else {
          // Update combined workletUrl, checking for inconsistencies.
          if (workletUrl === false) {
            workletUrl = item.url;
          } else if (workletUrl !== item.url) {
            workletUrl = true;  // Process used for different things.
          }

          if (workletType === WorkletType.NotWorklet) {
            workletType = item.workletType;
          } else if (workletType !== item.workletType) {
            workletType = WorkletType.UnknownWorklet;
          }
        }

        if (item.url) {
          if (item.main) {
            lastMainUrl = item.url;
          }
          lastUrl = item.url;
        }
      }

      for (const thread of process.sortedThreads()) {
        if (thread.name() === TimelineModelImpl.RendererMainThreadName) {
          this.processThreadEvents(
              tracingModel, ranges, thread, true /* isMainThread */, false /* isWorker */, hasMain,
              WorkletType.NotWorklet, hasMain ? lastMainUrl : lastUrl);
        } else if (
            thread.name() === TimelineModelImpl.WorkerThreadName ||
            thread.name() === TimelineModelImpl.WorkerThreadNameLegacy) {
          const workerMetaEvent = allMetadataEvents.find(e => {
            if (e.name !== TimelineModelImpl.DevToolsMetadataEvent.TracingSessionIdForWorker) {
              return false;
            }
            if (e.thread.process() !== process) {
              return false;
            }
            if (e.args['data']['workerThreadId'] !== thread.id()) {
              return false;
            }
            const frameId = TimelineModelImpl.eventFrameId(e);
            return frameId ? Boolean(this.pageFrames.get(frameId)) : false;
          });
          if (!workerMetaEvent) {
            continue;
          }
          this.workerIdByThread.set(thread, workerMetaEvent.args['data']['workerId'] || '');
          this.processThreadEvents(
              tracingModel, ranges, thread, false /* isMainThread */, true /* isWorker */, false /* forMainFrame */,
              WorkletType.NotWorklet, workerMetaEvent.args['data']['url'] || Platform.DevToolsPath.EmptyUrlString);
        } else {
          let urlForOther: Platform.DevToolsPath.UrlString|null = null;
          let workletTypeForOther: WorkletType = WorkletType.NotWorklet;
          if (thread.name() === TimelineModelImpl.AuctionWorkletThreadName ||
              thread.name() === TimelineModelImpl.UtilityMainThreadName) {
            if (typeof workletUrl !== 'boolean') {
              urlForOther = workletUrl;
            }
            workletTypeForOther = workletType;
          } else {
            // For processes that only do auction worklet things, skip other threads.
            if (allWorklet) {
              continue;
            }
          }
          this.processThreadEvents(
              tracingModel, ranges, thread, false /* isMainThread */, false /* isWorker */, false /* forMainFrame */,
              workletTypeForOther, urlForOther);
        }
      }
    }
  }

  private processMetadataEvents(tracingModel: SDK.TracingModel.TracingModel): MetadataEvents|null {
    const metadataEvents = tracingModel.devToolsMetadataEvents();

    const pageDevToolsMetadataEvents = [];
    const workersDevToolsMetadataEvents = [];
    for (const event of metadataEvents) {
      if (event.name === TimelineModelImpl.DevToolsMetadataEvent.TracingStartedInPage) {
        pageDevToolsMetadataEvents.push(event);
        if (event.args['data'] && event.args['data']['persistentIds']) {
          this.persistentIds = true;
        }
        const frames = ((event.args['data'] && event.args['data']['frames']) || [] as PageFrame[]);
        frames.forEach((payload: PageFrame) => this.addPageFrame(event, payload));
        this.mainFrame = this.rootFrames()[0];
      } else if (event.name === TimelineModelImpl.DevToolsMetadataEvent.TracingSessionIdForWorker) {
        workersDevToolsMetadataEvents.push(event);
      } else if (event.name === TimelineModelImpl.DevToolsMetadataEvent.TracingStartedInBrowser) {
        console.assert(!this.mainFrameNodeId, 'Multiple sessions in trace');
        this.mainFrameNodeId = event.args['frameTreeNodeId'];
      }
    }
    if (!pageDevToolsMetadataEvents.length) {
      return null;
    }

    const sessionId =
        pageDevToolsMetadataEvents[0].args['sessionId'] || pageDevToolsMetadataEvents[0].args['data']['sessionId'];
    this.sessionId = sessionId;

    const mismatchingIds = new Set<any>();
    function checkSessionId(event: SDK.TracingModel.Event): boolean {
      let args = event.args;
      // FIXME: put sessionId into args["data"] for TracingStartedInPage event.
      if (args['data']) {
        args = args['data'];
      }
      const id = args['sessionId'];
      if (id === sessionId) {
        return true;
      }
      mismatchingIds.add(id);
      return false;
    }
    const result = {
      page: pageDevToolsMetadataEvents.filter(checkSessionId).sort(SDK.TracingModel.Event.compareStartTime),
      workers: workersDevToolsMetadataEvents.sort(SDK.TracingModel.Event.compareStartTime),
    };
    if (mismatchingIds.size) {
      Common.Console.Console.instance().error(
          'Timeline recording was started in more than one page simultaneously. Session id mismatch: ' +
          this.sessionId + ' and ' + [...mismatchingIds] + '.');
    }
    return result;
  }

  private processSyncBrowserEvents(tracingModel: SDK.TracingModel.TracingModel): void {
    const browserMain = SDK.TracingModel.TracingModel.browserMainThread(tracingModel);
    if (browserMain) {
      browserMain.events().forEach(this.processBrowserEvent, this);
    }
  }

  private processAsyncBrowserEvents(tracingModel: SDK.TracingModel.TracingModel): void {
    const browserMain = SDK.TracingModel.TracingModel.browserMainThread(tracingModel);
    if (browserMain) {
      this.processAsyncEvents(browserMain, [{from: 0, to: Infinity}]);
    }
  }

  private buildGPUEvents(tracingModel: SDK.TracingModel.TracingModel): void {
    const thread = tracingModel.getThreadByName('GPU Process', 'CrGpuMain');
    if (!thread) {
      return;
    }
    const gpuEventName = RecordType.GPUTask;
    const track = this.ensureNamedTrack(TrackType.GPU);
    track.thread = thread;
    track.events = thread.events().filter(event => event.name === gpuEventName);
  }

  private buildLoadingEvents(tracingModel: SDK.TracingModel.TracingModel, events: SDK.TracingModel.Event[]): void {
    const thread = tracingModel.getThreadByName('Renderer', 'CrRendererMain');
    if (!thread) {
      return;
    }
    const experienceCategory = 'experience';
    const track = this.ensureNamedTrack(TrackType.Experience);
    track.thread = thread;
    track.events = events;

    // Even though the event comes from 'loading', in order to color it differently we
    // rename its category.
    for (const trackEvent of track.events) {
      trackEvent.categoriesString = experienceCategory;
      if (trackEvent.name === RecordType.LayoutShift) {
        const eventData = trackEvent.args['data'] || trackEvent.args['beginData'] || {};
        const timelineData = TimelineData.forEvent(trackEvent);
        if (eventData['impacted_nodes']) {
          for (let i = 0; i < eventData['impacted_nodes'].length; ++i) {
            timelineData.backendNodeIds.push(eventData['impacted_nodes'][i]['node_id']);
          }
        }
      }
    }
  }

  private resetProcessingState(): void {
    this.asyncEventTracker = new TimelineAsyncEventTracker();
    this.invalidationTracker = new InvalidationTracker();
    this.layoutInvalidate = {};
    this.lastScheduleStyleRecalculation = {};
    this.paintImageEventByPixelRefId = {};
    this.lastPaintForLayer = {};
    this.lastRecalculateStylesEvent = null;
    this.currentScriptEvent = null;
    this.eventStack = [];
    this.browserFrameTracking = false;
    this.persistentIds = false;
    this.legacyCurrentPage = null;
  }

  private extractCpuProfile(tracingModel: SDK.TracingModel.TracingModel, thread: SDK.TracingModel.Thread):
      SDK.CPUProfileDataModel.CPUProfileDataModel|null {
    const events = thread.events();
    let cpuProfile;
    let target: (SDK.Target.Target|null)|null = null;

    // Check for legacy CpuProfile event format first.
    let cpuProfileEvent: (SDK.TracingModel.Event|undefined)|SDK.TracingModel.Event = events[events.length - 1];
    if (cpuProfileEvent && cpuProfileEvent.name === RecordType.CpuProfile) {
      const eventData = cpuProfileEvent.args['data'];
      cpuProfile = (eventData && eventData['cpuProfile'] as Protocol.Profiler.Profile | null);
      target = this.targetByEvent(cpuProfileEvent);
    }

    if (!cpuProfile) {
      cpuProfileEvent = events.find(e => e.name === RecordType.Profile);
      if (!cpuProfileEvent) {
        return null;
      }
      target = this.targetByEvent(cpuProfileEvent);
      const profileGroup = tracingModel.profileGroup(cpuProfileEvent);
      if (!profileGroup) {
        Common.Console.Console.instance().error('Invalid CPU profile format.');
        return null;
      }
      cpuProfile = ({
        startTime: cpuProfileEvent.startTime * 1000,
        endTime: 0,
        nodes: [],
        samples: [],
        timeDeltas: [],
        lines: [],
      } as any);
      for (const profileEvent of profileGroup.children) {
        const eventData = profileEvent.args['data'];
        if ('startTime' in eventData) {
          // Do not use |eventData['startTime']| as it is in CLOCK_MONOTONIC domain,
          // but use |profileEvent.startTime| (|ts| in the trace event) which has
          // been translated to Perfetto's clock domain.
          //
          // Also convert from ms to us.
          cpuProfile.startTime = profileEvent.startTime * 1000;
        }
        if ('endTime' in eventData) {
          // Do not use |eventData['endTime']| as it is in CLOCK_MONOTONIC domain,
          // but use |profileEvent.startTime| (|ts| in the trace event) which has
          // been translated to Perfetto's clock domain.
          //
          // Despite its name, |profileEvent.startTime| was recorded right after
          // |eventData['endTime']| within v8 and is a reasonable substitute.
          //
          // Also convert from ms to us.
          cpuProfile.endTime = profileEvent.startTime * 1000;
        }
        const nodesAndSamples = eventData['cpuProfile'] || {};
        const samples = nodesAndSamples['samples'] || [];
        const lines = eventData['lines'] || Array(samples.length).fill(0);
        cpuProfile.nodes.push(...(nodesAndSamples['nodes'] || []));
        cpuProfile.lines.push(...lines);
        if (cpuProfile.samples) {
          cpuProfile.samples.push(...samples);
        }
        if (cpuProfile.timeDeltas) {
          cpuProfile.timeDeltas.push(...(eventData['timeDeltas'] || []));
        }
        if (cpuProfile.samples && cpuProfile.timeDeltas && cpuProfile.samples.length !== cpuProfile.timeDeltas.length) {
          Common.Console.Console.instance().error('Failed to parse CPU profile.');
          return null;
        }
      }
      if (!cpuProfile.endTime && cpuProfile.timeDeltas) {
        const timeDeltas: number[] = cpuProfile.timeDeltas;
        cpuProfile.endTime = timeDeltas.reduce((x, y) => x + y, cpuProfile.startTime);
      }
    }

    try {
      const profile = (cpuProfile as Protocol.Profiler.Profile);
      const jsProfileModel = new SDK.CPUProfileDataModel.CPUProfileDataModel(profile, target);
      this.cpuProfilesInternal.push(jsProfileModel);
      return jsProfileModel;
    } catch (e) {
      Common.Console.Console.instance().error('Failed to parse CPU profile.');
    }
    return null;
  }

  private injectJSFrameEvents(tracingModel: SDK.TracingModel.TracingModel, thread: SDK.TracingModel.Thread):
      SDK.TracingModel.Event[] {
    const jsProfileModel = this.extractCpuProfile(tracingModel, thread);
    let events = thread.events();
    const jsSamples =
        jsProfileModel ? TimelineJSProfileProcessor.generateTracingEventsFromCpuProfile(jsProfileModel, thread) : null;
    if (jsSamples && jsSamples.length) {
      events = Platform.ArrayUtilities.mergeOrdered(events, jsSamples, SDK.TracingModel.Event.orderedCompareStartTime);
    }
    if (jsSamples || events.some(e => e.name === RecordType.JSSample)) {
      const jsFrameEvents = TimelineJSProfileProcessor.generateJSFrameEvents(events, {
        showAllEvents: Root.Runtime.experiments.isEnabled('timelineShowAllEvents'),
        showRuntimeCallStats: Root.Runtime.experiments.isEnabled('timelineV8RuntimeCallStats'),
        showNativeFunctions: Common.Settings.Settings.instance().moduleSetting('showNativeFunctionsInJSProfile').get(),
      });
      if (jsFrameEvents && jsFrameEvents.length) {
        events =
            Platform.ArrayUtilities.mergeOrdered(jsFrameEvents, events, SDK.TracingModel.Event.orderedCompareStartTime);
      }
    }
    return events;
  }

  private static nameAuctionWorklet(workletType: WorkletType, url: Platform.DevToolsPath.UrlString|null): string {
    switch (workletType) {
      case WorkletType.BidderWorklet:
        return url ? i18nString(UIStrings.bidderWorkletS, {PH1: url}) : i18nString(UIStrings.bidderWorklet);

      case WorkletType.SellerWorklet:
        return url ? i18nString(UIStrings.sellerWorkletS, {PH1: url}) : i18nString(UIStrings.sellerWorklet);

      default:
        return url ? i18nString(UIStrings.unknownWorkletS, {PH1: url}) : i18nString(UIStrings.unknownWorklet);
    }
  }

  private processThreadEvents(
      tracingModel: SDK.TracingModel.TracingModel, ranges: {
        from: number,
        to: number,
      }[],
      thread: SDK.TracingModel.Thread, isMainThread: boolean, isWorker: boolean, forMainFrame: boolean,
      workletType: WorkletType, url: Platform.DevToolsPath.UrlString|null): void {
    const track = new Track();
    track.name = thread.name() || i18nString(UIStrings.threadS, {PH1: thread.id()});
    track.type = TrackType.Other;
    track.thread = thread;
    if (isMainThread) {
      track.type = TrackType.MainThread;
      track.url = url || Platform.DevToolsPath.EmptyUrlString;
      track.forMainFrame = forMainFrame;
    } else if (isWorker) {
      track.type = TrackType.Worker;
      track.url = url || Platform.DevToolsPath.EmptyUrlString;
      track.name = track.url ? i18nString(UIStrings.workerS, {PH1: track.url}) : i18nString(UIStrings.dedicatedWorker);
    } else if (thread.name().startsWith('CompositorTileWorker')) {
      track.type = TrackType.Raster;
    } else if (thread.name() === TimelineModelImpl.AuctionWorkletThreadName) {
      track.url = url || Platform.DevToolsPath.EmptyUrlString;
      track.name = TimelineModelImpl.nameAuctionWorklet(workletType, url);
    } else if (workletType !== WorkletType.NotWorklet && thread.name() === TimelineModelImpl.UtilityMainThreadName) {
      track.url = url || Platform.DevToolsPath.EmptyUrlString;
      track.name = url ? i18nString(UIStrings.workletServiceS, {PH1: url}) : i18nString(UIStrings.workletService);
    }
    this.tracksInternal.push(track);

    const events = this.injectJSFrameEvents(tracingModel, thread);
    this.eventStack = [];
    const eventStack = this.eventStack;

    // Get the worker name from the target.
    if (isWorker) {
      const cpuProfileEvent = events.find(event => event.name === RecordType.Profile);
      if (cpuProfileEvent) {
        const target = this.targetByEvent(cpuProfileEvent);
        if (target) {
          track.name = i18nString(UIStrings.workerSS, {PH1: target.name(), PH2: track.url});
        }
      }
    }

    for (const range of ranges) {
      let i = Platform.ArrayUtilities.lowerBound(events, range.from, (time, event) => time - event.startTime);
      for (; i < events.length; i++) {
        const event = events[i];
        if (event.startTime >= range.to) {
          break;
        }

        // There may be several TTI events, only take the first one.
        if (this.isInteractiveTimeEvent(event) && this.totalBlockingTimeInternal === -1) {
          this.totalBlockingTimeInternal = event.args['args']['total_blocking_time_ms'];
        }

        const isLongRunningTask = event.name === RecordType.Task && event.duration && event.duration > 50;
        if (isMainThread && isLongRunningTask && event.duration) {
          // We only track main thread events that are over 50ms, and the amount of time in the
          // event (over 50ms) is what constitutes the blocking time. An event of 70ms, therefore,
          // contributes 20ms to TBT.
          this.estimatedTotalBlockingTime += event.duration - 50;
        }

        let last: SDK.TracingModel.Event = eventStack[eventStack.length - 1];
        while (last && last.endTime !== undefined && last.endTime <= event.startTime) {
          eventStack.pop();
          last = eventStack[eventStack.length - 1];
        }
        if (!this.processEvent(event)) {
          continue;
        }
        if (!SDK.TracingModel.TracingModel.isAsyncPhase(event.phase) && event.duration) {
          if (eventStack.length) {
            const parent = eventStack[eventStack.length - 1];
            if (parent) {
              parent.selfTime -= event.duration;
              if (parent.selfTime < 0) {
                this.fixNegativeDuration(parent, event);
              }
            }
          }
          event.selfTime = event.duration;
          if (!eventStack.length) {
            track.tasks.push(event);
          }
          eventStack.push(event);
        }
        if (this.isMarkerEvent(event)) {
          this.timeMarkerEventsInternal.push(event);
        }

        track.events.push(event);
        this.inspectedTargetEventsInternal.push(event);
      }
    }
    this.processAsyncEvents(thread, ranges);
  }

  private fixNegativeDuration(event: SDK.TracingModel.Event, child: SDK.TracingModel.Event): void {
    const epsilon = 1e-3;
    if (event.selfTime < -epsilon) {
      console.error(
          `Children are longer than parent at ${event.startTime} ` +
          `(${(child.startTime - this.minimumRecordTime()).toFixed(3)} by ${(-event.selfTime).toFixed(3)}`);
    }
    event.selfTime = 0;
  }

  private processAsyncEvents(thread: SDK.TracingModel.Thread, ranges: {
    from: number,
    to: number,
  }[]): void {
    const asyncEvents = thread.asyncEvents();
    const groups = new Map<TrackType, SDK.TracingModel.AsyncEvent[]>();

    function group(type: TrackType): SDK.TracingModel.AsyncEvent[] {
      if (!groups.has(type)) {
        groups.set(type, []);
      }
      return groups.get(type) as SDK.TracingModel.AsyncEvent[];
    }

    for (const range of ranges) {
      let i = Platform.ArrayUtilities.lowerBound(asyncEvents, range.from, function(time, asyncEvent) {
        return time - asyncEvent.startTime;
      });

      for (; i < asyncEvents.length; ++i) {
        const asyncEvent = asyncEvents[i];
        if (asyncEvent.startTime >= range.to) {
          break;
        }

        if (asyncEvent.hasCategory(TimelineModelImpl.Category.Console)) {
          group(TrackType.Console).push(asyncEvent);
          continue;
        }

        if (asyncEvent.hasCategory(TimelineModelImpl.Category.UserTiming)) {
          group(TrackType.Timings).push(asyncEvent);
          continue;
        }

        if (asyncEvent.name === RecordType.Animation) {
          group(TrackType.Animation).push(asyncEvent);
          continue;
        }
      }
    }

    for (const [type, events] of groups) {
      const track = this.ensureNamedTrack(type);
      track.thread = thread;
      track.asyncEvents =
          Platform.ArrayUtilities.mergeOrdered(track.asyncEvents, events, SDK.TracingModel.Event.compareStartTime);
    }
  }

  private processEvent(event: SDK.TracingModel.Event): boolean {
    const eventStack = this.eventStack;

    if (!eventStack.length) {
      if (this.currentTaskLayoutAndRecalcEvents && this.currentTaskLayoutAndRecalcEvents.length) {
        const totalTime = this.currentTaskLayoutAndRecalcEvents.reduce((time, event) => {
          return event.duration === undefined ? time : time + event.duration;
        }, 0);
        if (totalTime > TimelineModelImpl.Thresholds.ForcedLayout) {
          for (const e of this.currentTaskLayoutAndRecalcEvents) {
            const timelineData = TimelineData.forEvent(e);
            timelineData.warning = e.name === RecordType.Layout ? TimelineModelImpl.WarningType.ForcedLayout :
                                                                  TimelineModelImpl.WarningType.ForcedStyle;
          }
        }
      }
      this.currentTaskLayoutAndRecalcEvents = [];
    }

    if (this.currentScriptEvent) {
      if (this.currentScriptEvent.endTime !== undefined && event.startTime > this.currentScriptEvent.endTime) {
        this.currentScriptEvent = null;
      }
    }

    const eventData = event.args['data'] || event.args['beginData'] || {};
    const timelineData = TimelineData.forEvent(event);
    if (eventData['stackTrace']) {
      timelineData.stackTrace = eventData['stackTrace'].map((callFrameOrProfileNode: Protocol.Runtime.CallFrame) => {
        // `callFrameOrProfileNode` can also be a `SDK.ProfileTreeModel.ProfileNode` for JSSample; that class
        // has accessors to mimic a `CallFrame`, but apparently we don't adjust stack traces in that case. Whether
        // we should is unclear.
        if (event.name !== RecordType.JSSample) {
          // We need to copy the data so we can safely modify it below.
          const frame = {...callFrameOrProfileNode};
          // TraceEvents come with 1-based line & column numbers. The frontend code
          // requires 0-based ones. Adjust the values.
          --frame.lineNumber;
          --frame.columnNumber;
          return frame;
        }
        return callFrameOrProfileNode;
      });
    }
    let pageFrameId = TimelineModelImpl.eventFrameId(event);
    const last = eventStack[eventStack.length - 1];
    if (!pageFrameId && last) {
      pageFrameId = TimelineData.forEvent(last).frameId;
    }
    timelineData.frameId = pageFrameId || (this.mainFrame && this.mainFrame.frameId) || '';
    this.asyncEventTracker.processEvent(event);

    if (this.isMarkerEvent(event)) {
      this.ensureNamedTrack(TrackType.Timings);
    }

    switch (event.name) {
      case RecordType.ResourceSendRequest:
      case RecordType.WebSocketCreate: {
        timelineData.setInitiator(eventStack[eventStack.length - 1] || null);
        timelineData.url = eventData['url'];
        break;
      }

      case RecordType.ScheduleStyleRecalculation: {
        this.lastScheduleStyleRecalculation[eventData['frame']] = event;
        break;
      }

      case RecordType.UpdateLayoutTree:
      case RecordType.RecalculateStyles: {
        this.invalidationTracker.didRecalcStyle(event);
        if (event.args['beginData']) {
          timelineData.setInitiator(this.lastScheduleStyleRecalculation[event.args['beginData']['frame']]);
        }
        this.lastRecalculateStylesEvent = event;
        if (this.currentScriptEvent) {
          this.currentTaskLayoutAndRecalcEvents.push(event);
        }
        break;
      }

      case RecordType.ScheduleStyleInvalidationTracking:
      case RecordType.StyleRecalcInvalidationTracking:
      case RecordType.StyleInvalidatorInvalidationTracking:
      case RecordType.LayoutInvalidationTracking: {
        this.invalidationTracker.addInvalidation(new InvalidationTrackingEvent(event, timelineData));
        break;
      }

      case RecordType.InvalidateLayout: {
        // Consider style recalculation as a reason for layout invalidation,
        // but only if we had no earlier layout invalidation records.
        let layoutInitator: (SDK.TracingModel.Event|null)|SDK.TracingModel.Event = event;
        const frameId = eventData['frame'];
        if (!this.layoutInvalidate[frameId] && this.lastRecalculateStylesEvent &&
            this.lastRecalculateStylesEvent.endTime !== undefined &&
            this.lastRecalculateStylesEvent.endTime > event.startTime) {
          layoutInitator = TimelineData.forEvent(this.lastRecalculateStylesEvent).initiator();
        }
        this.layoutInvalidate[frameId] = layoutInitator;
        break;
      }

      case RecordType.Layout: {
        this.invalidationTracker.didLayout(event);
        const frameId = event.args['beginData']['frame'];
        timelineData.setInitiator(this.layoutInvalidate[frameId]);
        // In case we have no closing Layout event, endData is not available.
        if (event.args['endData']) {
          if (event.args['endData']['layoutRoots']) {
            for (let i = 0; i < event.args['endData']['layoutRoots'].length; ++i) {
              timelineData.backendNodeIds.push(event.args['endData']['layoutRoots'][i]['nodeId']);
            }
          } else {
            timelineData.backendNodeIds.push(event.args['endData']['rootNode']);
          }
        }
        this.layoutInvalidate[frameId] = null;
        if (this.currentScriptEvent) {
          this.currentTaskLayoutAndRecalcEvents.push(event);
        }
        break;
      }

      case RecordType.Task: {
        if (event.duration !== undefined && event.duration > TimelineModelImpl.Thresholds.LongTask) {
          timelineData.warning = TimelineModelImpl.WarningType.LongTask;
        }
        break;
      }

      case RecordType.EventDispatch: {
        if (event.duration !== undefined && event.duration > TimelineModelImpl.Thresholds.RecurringHandler) {
          timelineData.warning = TimelineModelImpl.WarningType.LongHandler;
        }
        break;
      }

      case RecordType.TimerFire:
      case RecordType.FireAnimationFrame: {
        if (event.duration !== undefined && event.duration > TimelineModelImpl.Thresholds.RecurringHandler) {
          timelineData.warning = TimelineModelImpl.WarningType.LongRecurringHandler;
        }
        break;
      }
      // @ts-ignore fallthrough intended.
      case RecordType.FunctionCall: {
        // Compatibility with old format.
        if (typeof eventData['scriptName'] === 'string') {
          eventData['url'] = eventData['scriptName'];
        }
        if (typeof eventData['scriptLine'] === 'number') {
          eventData['lineNumber'] = eventData['scriptLine'];
        }
      }

      case RecordType.EvaluateScript:
      case RecordType.CompileScript:
      // @ts-ignore fallthrough intended.
      case RecordType.CacheScript: {
        if (typeof eventData['lineNumber'] === 'number') {
          --eventData['lineNumber'];
        }
        if (typeof eventData['columnNumber'] === 'number') {
          --eventData['columnNumber'];
        }
      }

      case RecordType.RunMicrotasks: {
        // Microtasks technically are not necessarily scripts, but for purpose of
        // forced sync style recalc or layout detection they are.
        if (!this.currentScriptEvent) {
          this.currentScriptEvent = event;
        }
        break;
      }

      case RecordType.SetLayerTreeId: {
        // This is to support old traces.
        if (this.sessionId && eventData['sessionId'] && this.sessionId === eventData['sessionId']) {
          this.mainFrameLayerTreeId = eventData['layerTreeId'];
          break;
        }

        // We currently only show layer tree for the main frame.
        const frameId = TimelineModelImpl.eventFrameId(event);
        const pageFrame = frameId ? this.pageFrames.get(frameId) : null;
        if (!pageFrame || pageFrame.parent) {
          return false;
        }
        this.mainFrameLayerTreeId = eventData['layerTreeId'];
        break;
      }

      case RecordType.Paint: {
        this.invalidationTracker.didPaint = true;
        // With CompositeAfterPaint enabled, paint events are no longer
        // associated with a Node, and nodeId will not be present.
        if ('nodeId' in eventData) {
          timelineData.backendNodeIds.push(eventData['nodeId']);
        }
        // Only keep layer paint events, skip paints for subframes that get painted to the same layer as parent.
        if (!eventData['layerId']) {
          break;
        }
        const layerId = eventData['layerId'];
        this.lastPaintForLayer[layerId] = event;
        break;
      }

      case RecordType.DisplayItemListSna