DevTools: reformat front-end code to match chromium style.

third_party/WebKit/Source/devtools/front_end/sdk/TracingModel.js

 /*
  * Copyright 2014 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-
 /**
- * @constructor
- * @param {!WebInspector.BackingStorage} backingStorage
+ * @unrestricted
  */
-WebInspector.TracingModel = function(backingStorage)
-{
+WebInspector.TracingModel = class {
+  /**
+   * @param {!WebInspector.BackingStorage} backingStorage
+   */
+  constructor(backingStorage) {
     this._backingStorage = backingStorage;
     // Avoid extra reset of the storage as it's expensive.
     this._firstWritePending = true;
     this.reset();
+  }
+
+  /**
+   * @param {string} phase
+   * @return {boolean}
+   */
+  static isNestableAsyncPhase(phase) {
+    return phase === 'b' || phase === 'e' || phase === 'n';
+  }
+
+  /**
+   * @param {string} phase
+   * @return {boolean}
+   */
+  static isAsyncBeginPhase(phase) {
+    return phase === 'S' || phase === 'b';
+  }
+
+  /**
+   * @param {string} phase
+   * @return {boolean}
+   */
+  static isAsyncPhase(phase) {
+    return WebInspector.TracingModel.isNestableAsyncPhase(phase) || phase === 'S' || phase === 'T' || phase === 'F' ||
+        phase === 'p';
+  }
+
+  /**
+   * @param {string} phase
+   * @return {boolean}
+   */
+  static isFlowPhase(phase) {
+    return phase === 's' || phase === 't' || phase === 'f';
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   * @return {boolean}
+   */
+  static isTopLevelEvent(event) {
+    return event.hasCategory(WebInspector.TracingModel.TopLevelEventCategory) ||
+        event.hasCategory(WebInspector.TracingModel.DevToolsMetadataEventCategory) &&
+        event.name === 'Program';  // Older timelines may have this instead of toplevel.
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   * @return {string|undefined}
+   */
+  static _extractId(payload) {
+    var scope = payload.scope || '';
+    if (typeof payload.id2 === 'undefined')
+      return scope && payload.id ? `${scope}@${payload.id}` : payload.id;
+    var id2 = payload.id2;
+    if (typeof id2 === 'object' && ('global' in id2) !== ('local' in id2))
+      return typeof id2['global'] !== 'undefined' ? `:${scope}:${id2['global']}` :
+                                                    `:${scope}:${payload.pid}:${id2['local']}`;
+    console.error(
+        `Unexpected id2 field at ${payload.ts / 1000}, one and only one of 'local' and 'global' should be present.`);
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel} tracingModel
+   * @return {?WebInspector.TracingModel.Thread}
+   *
+   * TODO: Move this to a better place. This is here just for convenience o
+   * re-use between modules. This really belongs to a higher level, since it
+   * is specific to chrome's usage of tracing.
+   */
+  static browserMainThread(tracingModel) {
+    var processes = tracingModel.sortedProcesses();
+    // Avoid warning for an empty model.
+    if (!processes.length)
+      return null;
+    var browserProcesses = [];
+    var crRendererMainThreads = [];
+    for (var process of processes) {
+      if (process.name().toLowerCase().endsWith('browser'))
+        browserProcesses.push(process);
+      crRendererMainThreads.push(...process.sortedThreads().filter(t => t.name() === 'CrBrowserMain'));
+    }
+    if (crRendererMainThreads.length === 1)
+      return crRendererMainThreads[0];
+    if (browserProcesses.length === 1)
+      return browserProcesses[0].threadByName('CrBrowserMain');
+    var tracingStartedInBrowser =
+        tracingModel.devToolsMetadataEvents().filter(e => e.name === 'TracingStartedInBrowser');
+    if (tracingStartedInBrowser.length === 1)
+      return tracingStartedInBrowser[0].thread;
+    WebInspector.console.error(
+        'Failed to find browser main thread in trace, some timeline features may be unavailable');
+    return null;
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.TracingModel.Event>}
+   */
+  devToolsMetadataEvents() {
+    return this._devToolsMetadataEvents;
+  }
+
+  /**
+   * @param {!Array.<!WebInspector.TracingManager.EventPayload>} events
+   */
+  setEventsForTest(events) {
+    this.reset();
+    this.addEvents(events);
+    this.tracingComplete();
+  }
+
+  /**
+   * @param {!Array.<!WebInspector.TracingManager.EventPayload>} events
+   */
+  addEvents(events) {
+    for (var i = 0; i < events.length; ++i)
+      this._addEvent(events[i]);
+  }
+
+  tracingComplete() {
+    this._processPendingAsyncEvents();
+    this._backingStorage.appendString(this._firstWritePending ? '[]' : ']');
+    this._backingStorage.finishWriting();
+    this._firstWritePending = false;
+    for (var process of this._processById.values()) {
+      for (var thread of process._threads.values())
+        thread.tracingComplete();
+    }
+  }
+
+  reset() {
+    /** @type {!Map<(number|string), !WebInspector.TracingModel.Process>} */
+    this._processById = new Map();
+    this._processByName = new Map();
+    this._minimumRecordTime = 0;
+    this._maximumRecordTime = 0;
+    this._devToolsMetadataEvents = [];
+    if (!this._firstWritePending)
+      this._backingStorage.reset();
+
+    this._firstWritePending = true;
+    /** @type {!Array<!WebInspector.TracingModel.Event>} */
+    this._asyncEvents = [];
+    /** @type {!Map<string, !WebInspector.TracingModel.AsyncEvent>} */
+    this._openAsyncEvents = new Map();
+    /** @type {!Map<string, !Array<!WebInspector.TracingModel.AsyncEvent>>} */
+    this._openNestableAsyncEvents = new Map();
+    /** @type {!Map<string, !WebInspector.TracingModel.ProfileEventsGroup>} */
+    this._profileGroups = new Map();
+    /** @type {!Map<string, !Set<string>>} */
+    this._parsedCategories = new Map();
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   */
+  _addEvent(payload) {
+    var process = this._processById.get(payload.pid);
+    if (!process) {
+      process = new WebInspector.TracingModel.Process(this, payload.pid);
+      this._processById.set(payload.pid, process);
+    }
+
+    var eventsDelimiter = ',\n';
+    this._backingStorage.appendString(this._firstWritePending ? '[' : eventsDelimiter);
+    this._firstWritePending = false;
+    var stringPayload = JSON.stringify(payload);
+    var isAccessible = payload.ph === WebInspector.TracingModel.Phase.SnapshotObject;
+    var backingStorage = null;
+    var keepStringsLessThan = 10000;
+    if (isAccessible && stringPayload.length > keepStringsLessThan)
+      backingStorage = this._backingStorage.appendAccessibleString(stringPayload);
+    else
+      this._backingStorage.appendString(stringPayload);
+
+    var timestamp = payload.ts / 1000;
+    // We do allow records for unrelated threads to arrive out-of-order,
+    // so there's a chance we're getting records from the past.
+    if (timestamp && (!this._minimumRecordTime || timestamp < this._minimumRecordTime))
+      this._minimumRecordTime = timestamp;
+    var endTimeStamp = (payload.ts + (payload.dur || 0)) / 1000;
+    this._maximumRecordTime = Math.max(this._maximumRecordTime, endTimeStamp);
+    var event = process._addEvent(payload);
+    if (!event)
+      return;
+    if (payload.ph === WebInspector.TracingModel.Phase.Sample) {
+      this._addSampleEvent(event);
+      return;
+    }
+    // Build async event when we've got events from all threads & processes, so we can sort them and process in the
+    // chronological order. However, also add individual async events to the thread flow (above), so we can easily
+    // display them on the same chart as other events, should we choose so.
+    if (WebInspector.TracingModel.isAsyncPhase(payload.ph))
+      this._asyncEvents.push(event);
+    event._setBackingStorage(backingStorage);
+    if (event.hasCategory(WebInspector.TracingModel.DevToolsMetadataEventCategory))
+      this._devToolsMetadataEvents.push(event);
+
+    if (payload.ph !== WebInspector.TracingModel.Phase.Metadata)
+      return;
+
+    switch (payload.name) {
+      case WebInspector.TracingModel.MetadataEvent.ProcessSortIndex:
+        process._setSortIndex(payload.args['sort_index']);
+        break;
+      case WebInspector.TracingModel.MetadataEvent.ProcessName:
+        var processName = payload.args['name'];
+        process._setName(processName);
+        this._processByName.set(processName, process);
+        break;
+      case WebInspector.TracingModel.MetadataEvent.ThreadSortIndex:
+        process.threadById(payload.tid)._setSortIndex(payload.args['sort_index']);
+        break;
+      case WebInspector.TracingModel.MetadataEvent.ThreadName:
+        process.threadById(payload.tid)._setName(payload.args['name']);
+        break;
+    }
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  _addSampleEvent(event) {
+    var group = this._profileGroups.get(event.id);
+    if (group)
+      group._addChild(event);
+    else
+      this._profileGroups.set(event.id, new WebInspector.TracingModel.ProfileEventsGroup(event));
+  }
+
+  /**
+   * @param {string} id
+   * @return {?WebInspector.TracingModel.ProfileEventsGroup}
+   */
+  profileGroup(id) {
+    return this._profileGroups.get(id) || null;
+  }
+
+  /**
+   * @return {number}
+   */
+  minimumRecordTime() {
+    return this._minimumRecordTime;
+  }
+
+  /**
+   * @return {number}
+   */
+  maximumRecordTime() {
+    return this._maximumRecordTime;
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.TracingModel.Process>}
+   */
+  sortedProcesses() {
+    return WebInspector.TracingModel.NamedObject._sort(this._processById.valuesArray());
+  }
+
+  /**
+   * @param {string} name
+   * @return {?WebInspector.TracingModel.Process}
+   */
+  processByName(name) {
+    return this._processByName.get(name);
+  }
+
+  /**
+   * @param {string} processName
+   * @param {string} threadName
+   * @return {?WebInspector.TracingModel.Thread}
+   */
+  threadByName(processName, threadName) {
+    var process = this.processByName(processName);
+    return process && process.threadByName(threadName);
+  }
+
+  _processPendingAsyncEvents() {
+    this._asyncEvents.stableSort(WebInspector.TracingModel.Event.compareStartTime);
+    for (var i = 0; i < this._asyncEvents.length; ++i) {
+      var event = this._asyncEvents[i];
+      if (WebInspector.TracingModel.isNestableAsyncPhase(event.phase))
+        this._addNestableAsyncEvent(event);
+      else
+        this._addAsyncEvent(event);
+    }
+    this._asyncEvents = [];
+    this._closeOpenAsyncEvents();
+  }
+
+  _closeOpenAsyncEvents() {
+    for (var event of this._openAsyncEvents.values()) {
+      event.setEndTime(this._maximumRecordTime);
+      // FIXME: remove this once we figure a better way to convert async console
+      // events to sync [waterfall] timeline records.
+      event.steps[0].setEndTime(this._maximumRecordTime);
+    }
+    this._openAsyncEvents.clear();
+
+    for (var eventStack of this._openNestableAsyncEvents.values()) {
+      while (eventStack.length)
+        eventStack.pop().setEndTime(this._maximumRecordTime);
+    }
+    this._openNestableAsyncEvents.clear();
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  _addNestableAsyncEvent(event) {
+    var phase = WebInspector.TracingModel.Phase;
+    var key = event.categoriesString + '.' + event.id;
+    var openEventsStack = this._openNestableAsyncEvents.get(key);
+
+    switch (event.phase) {
+      case phase.NestableAsyncBegin:
+        if (!openEventsStack) {
+          openEventsStack = [];
+          this._openNestableAsyncEvents.set(key, openEventsStack);
+        }
+        var asyncEvent = new WebInspector.TracingModel.AsyncEvent(event);
+        openEventsStack.push(asyncEvent);
+        event.thread._addAsyncEvent(asyncEvent);
+        break;
+
+      case phase.NestableAsyncInstant:
+        if (openEventsStack && openEventsStack.length)
+          openEventsStack.peekLast()._addStep(event);
+        break;
+
+      case phase.NestableAsyncEnd:
+        if (!openEventsStack || !openEventsStack.length)
+          break;
+        var top = openEventsStack.pop();
+        if (top.name !== event.name) {
+          console.error(
+              `Begin/end event mismatch for nestable async event, ${top.name} vs. ${event.name}, key: ${key}`);
+          break;
+        }
+        top._addStep(event);
+    }
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  _addAsyncEvent(event) {
+    var phase = WebInspector.TracingModel.Phase;
+    var key = event.categoriesString + '.' + event.name + '.' + event.id;
+    var asyncEvent = this._openAsyncEvents.get(key);
+
+    if (event.phase === phase.AsyncBegin) {
+      if (asyncEvent) {
+        console.error(`Event ${event.name} has already been started`);
+        return;
+      }
+      asyncEvent = new WebInspector.TracingModel.AsyncEvent(event);
+      this._openAsyncEvents.set(key, asyncEvent);
+      event.thread._addAsyncEvent(asyncEvent);
+      return;
+    }
+    if (!asyncEvent) {
+      // Quietly ignore stray async events, we're probably too late for the start.
+      return;
+    }
+    if (event.phase === phase.AsyncEnd) {
+      asyncEvent._addStep(event);
+      this._openAsyncEvents.delete(key);
+      return;
+    }
+    if (event.phase === phase.AsyncStepInto || event.phase === phase.AsyncStepPast) {
+      var lastStep = asyncEvent.steps.peekLast();
+      if (lastStep.phase !== phase.AsyncBegin && lastStep.phase !== event.phase) {
+        console.assert(
+            false, 'Async event step phase mismatch: ' + lastStep.phase + ' at ' + lastStep.startTime + ' vs. ' +
+                event.phase + ' at ' + event.startTime);
+        return;
+      }
+      asyncEvent._addStep(event);
+      return;
+    }
+    console.assert(false, 'Invalid async event phase');
+  }
+
+  /**
+   * @param {string} str
+   * @return {!Set<string>}
+   */
+  _parsedCategoriesForString(str) {
+    var parsedCategories = this._parsedCategories.get(str);
+    if (!parsedCategories) {
+      parsedCategories = new Set(str.split(','));
+      this._parsedCategories.set(str, parsedCategories);
+    }
+    return parsedCategories;
+  }
 };
 
 /**
  * @enum {string}
  */
 WebInspector.TracingModel.Phase = {
-    Begin: "B",
-    End: "E",
-    Complete: "X",
-    Instant: "I",
-    AsyncBegin: "S",
-    AsyncStepInto: "T",
-    AsyncStepPast: "p",
-    AsyncEnd: "F",
-    NestableAsyncBegin: "b",
-    NestableAsyncEnd: "e",
-    NestableAsyncInstant: "n",
-    FlowBegin: "s",
-    FlowStep: "t",
-    FlowEnd: "f",
-    Metadata: "M",
-    Counter: "C",
-    Sample: "P",
-    CreateObject: "N",
-    SnapshotObject: "O",
-    DeleteObject: "D"
+  Begin: 'B',
+  End: 'E',
+  Complete: 'X',
+  Instant: 'I',
+  AsyncBegin: 'S',
+  AsyncStepInto: 'T',
+  AsyncStepPast: 'p',
+  AsyncEnd: 'F',
+  NestableAsyncBegin: 'b',
+  NestableAsyncEnd: 'e',
+  NestableAsyncInstant: 'n',
+  FlowBegin: 's',
+  FlowStep: 't',
+  FlowEnd: 'f',
+  Metadata: 'M',
+  Counter: 'C',
+  Sample: 'P',
+  CreateObject: 'N',
+  SnapshotObject: 'O',
+  DeleteObject: 'D'
 };
 
 WebInspector.TracingModel.MetadataEvent = {
-    ProcessSortIndex: "process_sort_index",
-    ProcessName: "process_name",
-    ThreadSortIndex: "thread_sort_index",
-    ThreadName: "thread_name"
+  ProcessSortIndex: 'process_sort_index',
+  ProcessName: 'process_name',
+  ThreadSortIndex: 'thread_sort_index',
+  ThreadName: 'thread_name'
 };
 
-WebInspector.TracingModel.TopLevelEventCategory = "toplevel";
-WebInspector.TracingModel.DevToolsMetadataEventCategory = "disabled-by-default-devtools.timeline";
-WebInspector.TracingModel.DevToolsTimelineEventCategory = "disabled-by-default-devtools.timeline";
-
-WebInspector.TracingModel.FrameLifecycleEventCategory = "cc,devtools";
-
-/**
- * @param {string} phase
- * @return {boolean}
- */
-WebInspector.TracingModel.isNestableAsyncPhase = function(phase)
-{
-    return phase === "b" || phase === "e" || phase === "n";
-};
-
-/**
- * @param {string} phase
- * @return {boolean}
- */
-WebInspector.TracingModel.isAsyncBeginPhase = function(phase)
-{
-    return phase === "S" || phase === "b";
-};
-
-/**
- * @param {string} phase
- * @return {boolean}
- */
-WebInspector.TracingModel.isAsyncPhase = function(phase)
-{
-    return WebInspector.TracingModel.isNestableAsyncPhase(phase) || phase === "S" || phase === "T" || phase === "F" || phase === "p";
-};
-
-/**
- * @param {string} phase
- * @return {boolean}
- */
-WebInspector.TracingModel.isFlowPhase = function(phase)
-{
-    return phase === "s" || phase === "t" || phase === "f";
-};
-
-/**
- * @param {!WebInspector.TracingModel.Event} event
- * @return {boolean}
- */
-WebInspector.TracingModel.isTopLevelEvent = function(event)
-{
-    return event.hasCategory(WebInspector.TracingModel.TopLevelEventCategory) ||
-        event.hasCategory(WebInspector.TracingModel.DevToolsMetadataEventCategory) && event.name === "Program"; // Older timelines may have this instead of toplevel.
-};
-
-/**
- * @param {!WebInspector.TracingManager.EventPayload} payload
- * @return {string|undefined}
- */
-WebInspector.TracingModel._extractId = function(payload)
-{
-    var scope = payload.scope || "";
-    if (typeof payload.id2 === "undefined")
-        return scope && payload.id ? `${scope}@${payload.id}` : payload.id;
-    var id2 = payload.id2;
-    if (typeof id2 === "object" && ("global" in id2) !== ("local" in id2))
-        return typeof id2["global"] !== "undefined" ? `:${scope}:${id2["global"]}` : `:${scope}:${payload.pid}:${id2["local"]}`;
-    console.error(`Unexpected id2 field at ${payload.ts / 1000}, one and only one of 'local' and 'global' should be present.`);
-};
-
-/**
- * @param {!WebInspector.TracingModel} tracingModel
- * @return {?WebInspector.TracingModel.Thread}
- *
- * TODO: Move this to a better place. This is here just for convenience o
- * re-use between modules. This really belongs to a higher level, since it
- * is specific to chrome's usage of tracing.
- */
-WebInspector.TracingModel.browserMainThread = function(tracingModel)
-{
-    var processes = tracingModel.sortedProcesses();
-    // Avoid warning for an empty model.
-    if (!processes.length)
-        return null;
-    var browserProcesses = [];
-    var crRendererMainThreads = [];
-    for (var process of processes) {
-        if (process.name().toLowerCase().endsWith("browser"))
-            browserProcesses.push(process);
-        crRendererMainThreads.push(...process.sortedThreads().filter(t => t.name() === "CrBrowserMain"));
-    }
-    if (crRendererMainThreads.length === 1)
-        return crRendererMainThreads[0];
-    if (browserProcesses.length === 1)
-        return browserProcesses[0].threadByName("CrBrowserMain");
-    var tracingStartedInBrowser = tracingModel.devToolsMetadataEvents().filter(e => e.name === "TracingStartedInBrowser");
-    if (tracingStartedInBrowser.length === 1)
-        return tracingStartedInBrowser[0].thread;
-    WebInspector.console.error("Failed to find browser main thread in trace, some timeline features may be unavailable");
-    return null;
-};
+WebInspector.TracingModel.TopLevelEventCategory = 'toplevel';
+WebInspector.TracingModel.DevToolsMetadataEventCategory = 'disabled-by-default-devtools.timeline';
+WebInspector.TracingModel.DevToolsTimelineEventCategory = 'disabled-by-default-devtools.timeline';
+
+WebInspector.TracingModel.FrameLifecycleEventCategory = 'cc,devtools';
+
 
 /**
  * @interface
  */
-WebInspector.BackingStorage = function()
-{
+WebInspector.BackingStorage = function() {};
+
+WebInspector.BackingStorage.prototype = {
+  /**
+   * @param {string} string
+   */
+  appendString: function(string) {},
+
+  /**
+   * @param {string} string
+   * @return {function():!Promise.<?string>}
+   */
+  appendAccessibleString: function(string) {},
+
+  finishWriting: function() {},
+
+  reset: function() {},
 };
 
-WebInspector.BackingStorage.prototype = {
-    /**
-     * @param {string} string
-     */
-    appendString: function(string) { },
-
-    /**
-     * @param {string} string
-     * @return {function():!Promise.<?string>}
-     */
-    appendAccessibleString: function(string) { },
-
-    finishWriting: function() { },
-
-    reset: function() { },
-};
-
-
-WebInspector.TracingModel.prototype = {
-    /**
-     * @return {!Array.<!WebInspector.TracingModel.Event>}
-     */
-    devToolsMetadataEvents: function()
-    {
-        return this._devToolsMetadataEvents;
-    },
-
-    /**
-     * @param {!Array.<!WebInspector.TracingManager.EventPayload>} events
-     */
-    setEventsForTest: function(events)
-    {
-        this.reset();
-        this.addEvents(events);
-        this.tracingComplete();
-    },
-
-    /**
-     * @param {!Array.<!WebInspector.TracingManager.EventPayload>} events
-     */
-    addEvents: function(events)
-    {
-        for (var i = 0; i < events.length; ++i)
-            this._addEvent(events[i]);
-    },
-
-    tracingComplete: function()
-    {
-        this._processPendingAsyncEvents();
-        this._backingStorage.appendString(this._firstWritePending ? "[]" : "]");
-        this._backingStorage.finishWriting();
-        this._firstWritePending = false;
-        for (var process of this._processById.values()) {
-            for (var thread of process._threads.values())
-                thread.tracingComplete();
-        }
-    },
-
-    reset: function()
-    {
-        /** @type {!Map<(number|string), !WebInspector.TracingModel.Process>} */
-        this._processById = new Map();
-        this._processByName = new Map();
-        this._minimumRecordTime = 0;
-        this._maximumRecordTime = 0;
-        this._devToolsMetadataEvents = [];
-        if (!this._firstWritePending)
-            this._backingStorage.reset();
-
-        this._firstWritePending = true;
-        /** @type {!Array<!WebInspector.TracingModel.Event>} */
-        this._asyncEvents = [];
-        /** @type {!Map<string, !WebInspector.TracingModel.AsyncEvent>} */
-        this._openAsyncEvents = new Map();
-        /** @type {!Map<string, !Array<!WebInspector.TracingModel.AsyncEvent>>} */
-        this._openNestableAsyncEvents = new Map();
-        /** @type {!Map<string, !WebInspector.TracingModel.ProfileEventsGroup>} */
-        this._profileGroups = new Map();
-        /** @type {!Map<string, !Set<string>>} */
-        this._parsedCategories = new Map();
-    },
-
-    /**
-      * @param {!WebInspector.TracingManager.EventPayload} payload
-      */
-    _addEvent: function(payload)
-    {
-        var process = this._processById.get(payload.pid);
-        if (!process) {
-            process = new WebInspector.TracingModel.Process(this, payload.pid);
-            this._processById.set(payload.pid, process);
-        }
-
-        var eventsDelimiter = ",\n";
-        this._backingStorage.appendString(this._firstWritePending ? "[" : eventsDelimiter);
-        this._firstWritePending = false;
-        var stringPayload = JSON.stringify(payload);
-        var isAccessible = payload.ph === WebInspector.TracingModel.Phase.SnapshotObject;
-        var backingStorage = null;
-        var keepStringsLessThan = 10000;
-        if (isAccessible && stringPayload.length > keepStringsLessThan)
-            backingStorage = this._backingStorage.appendAccessibleString(stringPayload);
-        else
-            this._backingStorage.appendString(stringPayload);
-
-        var timestamp = payload.ts / 1000;
-        // We do allow records for unrelated threads to arrive out-of-order,
-        // so there's a chance we're getting records from the past.
-        if (timestamp && (!this._minimumRecordTime || timestamp < this._minimumRecordTime))
-            this._minimumRecordTime = timestamp;
-        var endTimeStamp = (payload.ts + (payload.dur || 0)) / 1000;
-        this._maximumRecordTime = Math.max(this._maximumRecordTime, endTimeStamp);
-        var event = process._addEvent(payload);
-        if (!event)
-            return;
-        if (payload.ph === WebInspector.TracingModel.Phase.Sample) {
-            this._addSampleEvent(event);
-            return;
-        }
-        // Build async event when we've got events from all threads & processes, so we can sort them and process in the
-        // chronological order. However, also add individual async events to the thread flow (above), so we can easily
-        // display them on the same chart as other events, should we choose so.
-        if (WebInspector.TracingModel.isAsyncPhase(payload.ph))
-            this._asyncEvents.push(event);
-        event._setBackingStorage(backingStorage);
-        if (event.hasCategory(WebInspector.TracingModel.DevToolsMetadataEventCategory))
-            this._devToolsMetadataEvents.push(event);
-
-        if (payload.ph !== WebInspector.TracingModel.Phase.Metadata)
-            return;
-
-        switch (payload.name) {
-        case WebInspector.TracingModel.MetadataEvent.ProcessSortIndex:
-            process._setSortIndex(payload.args["sort_index"]);
-            break;
-        case WebInspector.TracingModel.MetadataEvent.ProcessName:
-            var processName = payload.args["name"];
-            process._setName(processName);
-            this._processByName.set(processName, process);
-            break;
-        case WebInspector.TracingModel.MetadataEvent.ThreadSortIndex:
-            process.threadById(payload.tid)._setSortIndex(payload.args["sort_index"]);
-            break;
-        case WebInspector.TracingModel.MetadataEvent.ThreadName:
-            process.threadById(payload.tid)._setName(payload.args["name"]);
-            break;
-        }
-    },
-
-    /**
-     * @param {!WebInspector.TracingModel.Event} event
-     */
-    _addSampleEvent: function(event)
-    {
-        var group = this._profileGroups.get(event.id);
-        if (group)
-            group._addChild(event);
-        else
-            this._profileGroups.set(event.id, new WebInspector.TracingModel.ProfileEventsGroup(event));
-    },
-
-    /**
-     * @param {string} id
-     * @return {?WebInspector.TracingModel.ProfileEventsGroup}
-     */
-    profileGroup: function(id)
-    {
-        return this._profileGroups.get(id) || null;
-    },
-
-    /**
-     * @return {number}
-     */
-    minimumRecordTime: function()
-    {
-        return this._minimumRecordTime;
-    },
-
-    /**
-     * @return {number}
-     */
-    maximumRecordTime: function()
-    {
-        return this._maximumRecordTime;
-    },
-
-    /**
-     * @return {!Array.<!WebInspector.TracingModel.Process>}
-     */
-    sortedProcesses: function()
-    {
-        return WebInspector.TracingModel.NamedObject._sort(this._processById.valuesArray());
-    },
-
-    /**
-     * @param {string} name
-     * @return {?WebInspector.TracingModel.Process}
-     */
-    processByName: function(name)
-    {
-        return this._processByName.get(name);
-    },
-
-    /**
-     * @param {string} processName
-     * @param {string} threadName
-     * @return {?WebInspector.TracingModel.Thread}
-     */
-    threadByName: function(processName, threadName)
-    {
-        var process = this.processByName(processName);
-        return process && process.threadByName(threadName);
-    },
-
-    _processPendingAsyncEvents: function()
-    {
-        this._asyncEvents.stableSort(WebInspector.TracingModel.Event.compareStartTime);
-        for (var i = 0; i < this._asyncEvents.length; ++i) {
-            var event = this._asyncEvents[i];
-            if (WebInspector.TracingModel.isNestableAsyncPhase(event.phase))
-                this._addNestableAsyncEvent(event);
-            else
-                this._addAsyncEvent(event);
-        }
-        this._asyncEvents = [];
-        this._closeOpenAsyncEvents();
-    },
-
-    _closeOpenAsyncEvents: function()
-    {
-        for (var event of this._openAsyncEvents.values()) {
-            event.setEndTime(this._maximumRecordTime);
-            // FIXME: remove this once we figure a better way to convert async console
-            // events to sync [waterfall] timeline records.
-            event.steps[0].setEndTime(this._maximumRecordTime);
-        }
-        this._openAsyncEvents.clear();
-
-        for (var eventStack of this._openNestableAsyncEvents.values()) {
-            while (eventStack.length)
-                eventStack.pop().setEndTime(this._maximumRecordTime);
-        }
-        this._openNestableAsyncEvents.clear();
-    },
-
-    /**
-     * @param {!WebInspector.TracingModel.Event} event
-     */
-    _addNestableAsyncEvent: function(event)
-    {
-        var phase = WebInspector.TracingModel.Phase;
-        var key = event.categoriesString + "." + event.id;
-        var openEventsStack = this._openNestableAsyncEvents.get(key);
-
-        switch (event.phase) {
-        case phase.NestableAsyncBegin:
-            if (!openEventsStack) {
-                openEventsStack = [];
-                this._openNestableAsyncEvents.set(key, openEventsStack);
-            }
-            var asyncEvent = new WebInspector.TracingModel.AsyncEvent(event);
-            openEventsStack.push(asyncEvent);
-            event.thread._addAsyncEvent(asyncEvent);
-            break;
-
-        case phase.NestableAsyncInstant:
-            if (openEventsStack && openEventsStack.length)
-                openEventsStack.peekLast()._addStep(event);
-            break;
-
-        case phase.NestableAsyncEnd:
-            if (!openEventsStack || !openEventsStack.length)
-                break;
-            var top = openEventsStack.pop();
-            if (top.name !== event.name) {
-                console.error(`Begin/end event mismatch for nestable async event, ${top.name} vs. ${event.name}, key: ${key}`);
-                break;
-            }
-            top._addStep(event);
-        }
-    },
-
-    /**
-     * @param {!WebInspector.TracingModel.Event} event
-     */
-    _addAsyncEvent: function(event)
-    {
-        var phase = WebInspector.TracingModel.Phase;
-        var key = event.categoriesString + "." + event.name + "." + event.id;
-        var asyncEvent = this._openAsyncEvents.get(key);
-
-        if (event.phase === phase.AsyncBegin) {
-            if (asyncEvent) {
-                console.error(`Event ${event.name} has already been started`);
-                return;
-            }
-            asyncEvent = new WebInspector.TracingModel.AsyncEvent(event);
-            this._openAsyncEvents.set(key, asyncEvent);
-            event.thread._addAsyncEvent(asyncEvent);
-            return;
-        }
-        if (!asyncEvent) {
-            // Quietly ignore stray async events, we're probably too late for the start.
-            return;
-        }
-        if (event.phase === phase.AsyncEnd) {
-            asyncEvent._addStep(event);
-            this._openAsyncEvents.delete(key);
-            return;
-        }
-        if (event.phase === phase.AsyncStepInto || event.phase === phase.AsyncStepPast) {
-            var lastStep = asyncEvent.steps.peekLast();
-            if (lastStep.phase !== phase.AsyncBegin && lastStep.phase !== event.phase) {
-                console.assert(false, "Async event step phase mismatch: " + lastStep.phase + " at " + lastStep.startTime + " vs. " + event.phase + " at " + event.startTime);
-                return;
-            }
-            asyncEvent._addStep(event);
-            return;
-        }
-        console.assert(false, "Invalid async event phase");
-    },
-
-    /**
-     * @param {string} str
-     * @return {!Set<string>}
-     */
-    _parsedCategoriesForString: function(str)
-    {
-        var parsedCategories = this._parsedCategories.get(str);
-        if (!parsedCategories) {
-            parsedCategories = new Set(str.split(","));
-            this._parsedCategories.set(str, parsedCategories);
-        }
-        return parsedCategories;
-    }
-};
-
 /**
- * @constructor
- * @param {string} categories
- * @param {string} name
- * @param {!WebInspector.TracingModel.Phase} phase
- * @param {number} startTime
- * @param {!WebInspector.TracingModel.Thread} thread
+ * @unrestricted
  */
-WebInspector.TracingModel.Event = function(categories, name, phase, startTime, thread)
-{
+WebInspector.TracingModel.Event = class {
+  /**
+   * @param {string} categories
+   * @param {string} name
+   * @param {!WebInspector.TracingModel.Phase} phase
+   * @param {number} startTime
+   * @param {!WebInspector.TracingModel.Thread} thread
+   */
+  constructor(categories, name, phase, startTime, thread) {
     /** @type {string} */
     this.categoriesString = categories;
     /** @type {!Set<string>} */
     this._parsedCategories = thread._model._parsedCategoriesForString(categories);
     /** @type {string} */
     this.name = name;
     /** @type {!WebInspector.TracingModel.Phase} */
     this.phase = phase;
     /** @type {number} */
     this.startTime = startTime;
@@ skipping 10 matching lines @@
     this.stackTrace = null;
     /** @type {?Element} */
     this.previewElement = null;
     /** @type {?string} */
     this.url = null;
     /** @type {number} */
     this.backendNodeId = 0;
 
     /** @type {number} */
     this.selfTime = 0;
-};
-
-/**
- * @param {!WebInspector.TracingManager.EventPayload} payload
- * @param {!WebInspector.TracingModel.Thread} thread
- * @return {!WebInspector.TracingModel.Event}
- */
-WebInspector.TracingModel.Event.fromPayload = function(payload, thread)
-{
-    var event = new WebInspector.TracingModel.Event(payload.cat, payload.name, /** @type {!WebInspector.TracingModel.Phase} */ (payload.ph), payload.ts / 1000, thread);
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   * @param {!WebInspector.TracingModel.Thread} thread
+   * @return {!WebInspector.TracingModel.Event}
+   */
+  static fromPayload(payload, thread) {
+    var event = new WebInspector.TracingModel.Event(
+        payload.cat, payload.name, /** @type {!WebInspector.TracingModel.Phase} */ (payload.ph), payload.ts / 1000,
+        thread);
     if (payload.args)
-        event.addArgs(payload.args);
+      event.addArgs(payload.args);
     else
-        console.error("Missing mandatory event argument 'args' at " + payload.ts / 1000);
-    if (typeof payload.dur === "number")
-        event.setEndTime((payload.ts + payload.dur) / 1000);
+      console.error('Missing mandatory event argument \'args\' at ' + payload.ts / 1000);
+    if (typeof payload.dur === 'number')
+      event.setEndTime((payload.ts + payload.dur) / 1000);
     var id = WebInspector.TracingModel._extractId(payload);
-    if (typeof id !== "undefined")
-        event.id = id;
+    if (typeof id !== 'undefined')
+      event.id = id;
     if (payload.bind_id)
-        event.bind_id = payload.bind_id;
+      event.bind_id = payload.bind_id;
 
     return event;
-};
-
-WebInspector.TracingModel.Event.prototype = {
-    /**
-     * @param {string} categoryName
-     * @return {boolean}
-     */
-    hasCategory: function(categoryName)
-    {
-        return this._parsedCategories.has(categoryName);
-    },
-
-    /**
-     * @param {number} endTime
-     */
-    setEndTime: function(endTime)
-    {
-        if (endTime < this.startTime) {
-            console.assert(false, "Event out of order: " + this.name);
-            return;
-        }
-        this.endTime = endTime;
-        this.duration = endTime - this.startTime;
-    },
-
-    /**
-     * @param {!Object} args
-     */
-    addArgs: function(args)
-    {
-        // Shallow copy args to avoid modifying original payload which may be saved to file.
-        for (var name in args) {
-            if (name in this.args)
-                console.error("Same argument name (" + name +  ") is used for begin and end phases of " + this.name);
-            this.args[name] = args[name];
-        }
-    },
-
-    /**
-     * @param {!WebInspector.TracingModel.Event} endEvent
-     */
-    _complete: function(endEvent)
-    {
-        if (endEvent.args)
-            this.addArgs(endEvent.args);
-        else
-            console.error("Missing mandatory event argument 'args' at " + endEvent.startTime);
-        this.setEndTime(endEvent.startTime);
-    },
-
-    /**
-     * @param {?function():!Promise.<?string>} backingStorage
-     */
-    _setBackingStorage: function(backingStorage)
-    {
-    }
-};
-
-/**
- * @param {!WebInspector.TracingModel.Event} a
- * @param {!WebInspector.TracingModel.Event} b
- * @return {number}
- */
-WebInspector.TracingModel.Event.compareStartTime = function(a, b)
-{
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} a
+   * @param {!WebInspector.TracingModel.Event} b
+   * @return {number}
+   */
+  static compareStartTime(a, b) {
     return a.startTime - b.startTime;
-};
-
-/**
- * @param {!WebInspector.TracingModel.Event} a
- * @param {!WebInspector.TracingModel.Event} b
- * @return {number}
- */
-WebInspector.TracingModel.Event.compareStartAndEndTime = function(a, b)
-{
-    return a.startTime - b.startTime || (b.endTime !== undefined && a.endTime !== undefined && b.endTime - a.endTime) || 0;
-};
-
-/**
- * @param {!WebInspector.TracingModel.Event} a
- * @param {!WebInspector.TracingModel.Event} b
- * @return {number}
- */
-WebInspector.TracingModel.Event.orderedCompareStartTime = function(a, b)
-{
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} a
+   * @param {!WebInspector.TracingModel.Event} b
+   * @return {number}
+   */
+  static compareStartAndEndTime(a, b) {
+    return a.startTime - b.startTime || (b.endTime !== undefined && a.endTime !== undefined && b.endTime - a.endTime) ||
+        0;
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} a
+   * @param {!WebInspector.TracingModel.Event} b
+   * @return {number}
+   */
+  static orderedCompareStartTime(a, b) {
     // Array.mergeOrdered coalesces objects if comparator returns 0.
     // To change this behavior this comparator return -1 in the case events
     // startTime's are equal, so both events got placed into the result array.
     return a.startTime - b.startTime || a.ordinal - b.ordinal || -1;
-};
-
-/**
- * @constructor
- * @extends {WebInspector.TracingModel.Event}
- * @param {string} category
- * @param {string} name
- * @param {number} startTime
- * @param {!WebInspector.TracingModel.Thread} thread
- */
-WebInspector.TracingModel.ObjectSnapshot = function(category, name, startTime, thread)
-{
-    WebInspector.TracingModel.Event.call(this, category, name, WebInspector.TracingModel.Phase.SnapshotObject, startTime, thread);
-};
-
-/**
- * @param {!WebInspector.TracingManager.EventPayload} payload
- * @param {!WebInspector.TracingModel.Thread} thread
- * @return {!WebInspector.TracingModel.ObjectSnapshot}
- */
-WebInspector.TracingModel.ObjectSnapshot.fromPayload = function(payload, thread)
-{
+  }
+
+  /**
+   * @param {string} categoryName
+   * @return {boolean}
+   */
+  hasCategory(categoryName) {
+    return this._parsedCategories.has(categoryName);
+  }
+
+  /**
+   * @param {number} endTime
+   */
+  setEndTime(endTime) {
+    if (endTime < this.startTime) {
+      console.assert(false, 'Event out of order: ' + this.name);
+      return;
+    }
+    this.endTime = endTime;
+    this.duration = endTime - this.startTime;
+  }
+
+  /**
+   * @param {!Object} args
+   */
+  addArgs(args) {
+    // Shallow copy args to avoid modifying original payload which may be saved to file.
+    for (var name in args) {
+      if (name in this.args)
+        console.error('Same argument name (' + name + ') is used for begin and end phases of ' + this.name);
+      this.args[name] = args[name];
+    }
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} endEvent
+   */
+  _complete(endEvent) {
+    if (endEvent.args)
+      this.addArgs(endEvent.args);
+    else
+      console.error('Missing mandatory event argument \'args\' at ' + endEvent.startTime);
+    this.setEndTime(endEvent.startTime);
+  }
+
+  /**
+   * @param {?function():!Promise.<?string>} backingStorage
+   */
+  _setBackingStorage(backingStorage) {
+  }
+};
+
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.ObjectSnapshot = class extends WebInspector.TracingModel.Event {
+  /**
+   * @param {string} category
+   * @param {string} name
+   * @param {number} startTime
+   * @param {!WebInspector.TracingModel.Thread} thread
+   */
+  constructor(category, name, startTime, thread) {
+    super(category, name, WebInspector.TracingModel.Phase.SnapshotObject, startTime, thread);
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   * @param {!WebInspector.TracingModel.Thread} thread
+   * @return {!WebInspector.TracingModel.ObjectSnapshot}
+   */
+  static fromPayload(payload, thread) {
     var snapshot = new WebInspector.TracingModel.ObjectSnapshot(payload.cat, payload.name, payload.ts / 1000, thread);
     var id = WebInspector.TracingModel._extractId(payload);
-    if (typeof id !== "undefined")
-        snapshot.id = id;
-    if (!payload.args || !payload.args["snapshot"]) {
-        console.error("Missing mandatory 'snapshot' argument at " + payload.ts / 1000);
-        return snapshot;
+    if (typeof id !== 'undefined')
+      snapshot.id = id;
+    if (!payload.args || !payload.args['snapshot']) {
+      console.error('Missing mandatory \'snapshot\' argument at ' + payload.ts / 1000);
+      return snapshot;
     }
     if (payload.args)
-        snapshot.addArgs(payload.args);
+      snapshot.addArgs(payload.args);
     return snapshot;
-};
-
-WebInspector.TracingModel.ObjectSnapshot.prototype = {
+  }
+
+  /**
+   * @param {function(?)} callback
+   */
+  requestObject(callback) {
+    var snapshot = this.args['snapshot'];
+    if (snapshot) {
+      callback(snapshot);
+      return;
+    }
+    this._backingStorage().then(onRead, callback.bind(null, null));
     /**
-     * @param {function(?)} callback
+     * @param {?string} result
      */
-    requestObject: function(callback)
-    {
-        var snapshot = this.args["snapshot"];
-        if (snapshot) {
-            callback(snapshot);
-            return;
-        }
-        this._backingStorage().then(onRead, callback.bind(null, null));
-        /**
-         * @param {?string} result
-         */
-        function onRead(result)
-        {
-            if (!result) {
-                callback(null);
-                return;
-            }
-            try {
-                var payload = JSON.parse(result);
-                callback(payload["args"]["snapshot"]);
-            } catch (e) {
-                WebInspector.console.error("Malformed event data in backing storage");
-                callback(null);
-            }
-        }
-    },
-
-    /**
-     * @return {!Promise<?>}
-     */
-    objectPromise: function()
-    {
-        if (!this._objectPromise)
-            this._objectPromise = new Promise(this.requestObject.bind(this));
-        return this._objectPromise;
-    },
-
-    /**
-     * @override
-     * @param {?function():!Promise.<?>} backingStorage
-     */
-    _setBackingStorage: function(backingStorage)
-    {
-        if (!backingStorage)
-            return;
-        this._backingStorage = backingStorage;
-        this.args = {};
-    },
-
-    __proto__: WebInspector.TracingModel.Event.prototype
-};
-
-/**
- * @constructor
- * @param {!WebInspector.TracingModel.Event} startEvent
- * @extends {WebInspector.TracingModel.Event}
- */
-WebInspector.TracingModel.AsyncEvent = function(startEvent)
-{
-    WebInspector.TracingModel.Event.call(this, startEvent.categoriesString, startEvent.name, startEvent.phase, startEvent.startTime, startEvent.thread);
+    function onRead(result) {
+      if (!result) {
+        callback(null);
+        return;
+      }
+      try {
+        var payload = JSON.parse(result);
+        callback(payload['args']['snapshot']);
+      } catch (e) {
+        WebInspector.console.error('Malformed event data in backing storage');
+        callback(null);
+      }
+    }
+  }
+
+  /**
+   * @return {!Promise<?>}
+   */
+  objectPromise() {
+    if (!this._objectPromise)
+      this._objectPromise = new Promise(this.requestObject.bind(this));
+    return this._objectPromise;
+  }
+
+  /**
+   * @override
+   * @param {?function():!Promise.<?>} backingStorage
+   */
+  _setBackingStorage(backingStorage) {
+    if (!backingStorage)
+      return;
+    this._backingStorage = backingStorage;
+    this.args = {};
+  }
+};
+
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.AsyncEvent = class extends WebInspector.TracingModel.Event {
+  /**
+   * @param {!WebInspector.TracingModel.Event} startEvent
+   */
+  constructor(startEvent) {
+    super(startEvent.categoriesString, startEvent.name, startEvent.phase, startEvent.startTime, startEvent.thread);
     this.addArgs(startEvent.args);
     this.steps = [startEvent];
-};
-
-WebInspector.TracingModel.AsyncEvent.prototype = {
-    /**
-     * @param {!WebInspector.TracingModel.Event} event
-     */
-    _addStep: function(event)
-    {
-        this.steps.push(event);
-        if (event.phase === WebInspector.TracingModel.Phase.AsyncEnd || event.phase === WebInspector.TracingModel.Phase.NestableAsyncEnd) {
-            this.setEndTime(event.startTime);
-            // FIXME: ideally, we shouldn't do this, but this makes the logic of converting
-            // async console events to sync ones much simpler.
-            this.steps[0].setEndTime(event.startTime);
-        }
-    },
-
-    __proto__: WebInspector.TracingModel.Event.prototype
-};
-
-/**
- * @constructor
- * @param {!WebInspector.TracingModel.Event} event
- */
-WebInspector.TracingModel.ProfileEventsGroup = function(event)
-{
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  _addStep(event) {
+    this.steps.push(event);
+    if (event.phase === WebInspector.TracingModel.Phase.AsyncEnd ||
+        event.phase === WebInspector.TracingModel.Phase.NestableAsyncEnd) {
+      this.setEndTime(event.startTime);
+      // FIXME: ideally, we shouldn't do this, but this makes the logic of converting
+      // async console events to sync ones much simpler.
+      this.steps[0].setEndTime(event.startTime);
+    }
+  }
+};
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.ProfileEventsGroup = class {
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  constructor(event) {
     /** @type {!Array<!WebInspector.TracingModel.Event>} */
     this.children = [event];
-};
-
-WebInspector.TracingModel.ProfileEventsGroup.prototype = {
-    /**
-     * @param {!WebInspector.TracingModel.Event} event
-     */
-    _addChild: function(event)
-    {
-        this.children.push(event);
-    }
-};
-
-/**
- * @constructor
- */
-WebInspector.TracingModel.NamedObject = function()
-{
-};
-
-WebInspector.TracingModel.NamedObject.prototype =
-{
-    /**
-     * @param {string} name
-     */
-    _setName: function(name)
-    {
-        this._name = name;
-    },
-
-    /**
-     * @return {string}
-     */
-    name: function()
-    {
-        return this._name;
-    },
-
-    /**
-     * @param {number} sortIndex
-     */
-    _setSortIndex: function(sortIndex)
-    {
-        this._sortIndex = sortIndex;
-    },
-};
-
-/**
- * @param {!Array.<!WebInspector.TracingModel.NamedObject>} array
- */
-WebInspector.TracingModel.NamedObject._sort = function(array)
-{
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.Event} event
+   */
+  _addChild(event) {
+    this.children.push(event);
+  }
+};
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.NamedObject = class {
+  /**
+   * @param {!Array.<!WebInspector.TracingModel.NamedObject>} array
+   */
+  static _sort(array) {
     /**
      * @param {!WebInspector.TracingModel.NamedObject} a
      * @param {!WebInspector.TracingModel.NamedObject} b
      */
-    function comparator(a, b)
-    {
-        return a._sortIndex !== b._sortIndex ? a._sortIndex - b._sortIndex : a.name().localeCompare(b.name());
+    function comparator(a, b) {
+      return a._sortIndex !== b._sortIndex ? a._sortIndex - b._sortIndex : a.name().localeCompare(b.name());
     }
     return array.sort(comparator);
-};
-
-/**
- * @constructor
- * @extends {WebInspector.TracingModel.NamedObject}
- * @param {!WebInspector.TracingModel} model
- * @param {number} id
- */
-WebInspector.TracingModel.Process = function(model, id)
-{
-    WebInspector.TracingModel.NamedObject.call(this);
-    this._setName("Process " + id);
+  }
+
+  /**
+   * @param {string} name
+   */
+  _setName(name) {
+    this._name = name;
+  }
+
+  /**
+   * @return {string}
+   */
+  name() {
+    return this._name;
+  }
+
+  /**
+   * @param {number} sortIndex
+   */
+  _setSortIndex(sortIndex) {
+    this._sortIndex = sortIndex;
+  }
+};
+
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.Process = class extends WebInspector.TracingModel.NamedObject {
+  /**
+   * @param {!WebInspector.TracingModel} model
+   * @param {number} id
+   */
+  constructor(model, id) {
+    super();
+    this._setName('Process ' + id);
     this._id = id;
     /** @type {!Map<number, !WebInspector.TracingModel.Thread>} */
     this._threads = new Map();
     this._threadByName = new Map();
     this._model = model;
-};
-
-WebInspector.TracingModel.Process.prototype = {
-    /**
-     * @return {number}
-     */
-    id: function()
-    {
-        return this._id;
-    },
-
-    /**
-     * @param {number} id
-     * @return {!WebInspector.TracingModel.Thread}
-     */
-    threadById: function(id)
-    {
-        var thread = this._threads.get(id);
-        if (!thread) {
-            thread = new WebInspector.TracingModel.Thread(this, id);
-            this._threads.set(id, thread);
-        }
-        return thread;
-    },
-
-    /**
-     * @param {string} name
-     * @return {?WebInspector.TracingModel.Thread}
-     */
-    threadByName: function(name)
-    {
-        return this._threadByName.get(name) || null;
-    },
-
-    /**
-     * @param {string} name
-     * @param {!WebInspector.TracingModel.Thread} thread
-     */
-    _setThreadByName: function(name, thread)
-    {
-        this._threadByName.set(name, thread);
-    },
-
-    /**
-     * @param {!WebInspector.TracingManager.EventPayload} payload
-     * @return {?WebInspector.TracingModel.Event} event
-     */
-    _addEvent: function(payload)
-    {
-        return this.threadById(payload.tid)._addEvent(payload);
-    },
-
-    /**
-     * @return {!Array.<!WebInspector.TracingModel.Thread>}
-     */
-    sortedThreads: function()
-    {
-        return WebInspector.TracingModel.NamedObject._sort(this._threads.valuesArray());
-    },
-
-    __proto__: WebInspector.TracingModel.NamedObject.prototype
-};
-
-/**
- * @constructor
- * @extends {WebInspector.TracingModel.NamedObject}
- * @param {!WebInspector.TracingModel.Process} process
- * @param {number} id
- */
-WebInspector.TracingModel.Thread = function(process, id)
-{
-    WebInspector.TracingModel.NamedObject.call(this);
+  }
+
+  /**
+   * @return {number}
+   */
+  id() {
+    return this._id;
+  }
+
+  /**
+   * @param {number} id
+   * @return {!WebInspector.TracingModel.Thread}
+   */
+  threadById(id) {
+    var thread = this._threads.get(id);
+    if (!thread) {
+      thread = new WebInspector.TracingModel.Thread(this, id);
+      this._threads.set(id, thread);
+    }
+    return thread;
+  }
+
+  /**
+   * @param {string} name
+   * @return {?WebInspector.TracingModel.Thread}
+   */
+  threadByName(name) {
+    return this._threadByName.get(name) || null;
+  }
+
+  /**
+   * @param {string} name
+   * @param {!WebInspector.TracingModel.Thread} thread
+   */
+  _setThreadByName(name, thread) {
+    this._threadByName.set(name, thread);
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   * @return {?WebInspector.TracingModel.Event} event
+   */
+  _addEvent(payload) {
+    return this.threadById(payload.tid)._addEvent(payload);
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.TracingModel.Thread>}
+   */
+  sortedThreads() {
+    return WebInspector.TracingModel.NamedObject._sort(this._threads.valuesArray());
+  }
+};
+
+/**
+ * @unrestricted
+ */
+WebInspector.TracingModel.Thread = class extends WebInspector.TracingModel.NamedObject {
+  /**
+   * @param {!WebInspector.TracingModel.Process} process
+   * @param {number} id
+   */
+  constructor(process, id) {
+    super();
     this._process = process;
-    this._setName("Thread " + id);
+    this._setName('Thread ' + id);
     this._events = [];
     this._asyncEvents = [];
     this._id = id;
     this._model = process._model;
-};
-
-WebInspector.TracingModel.Thread.prototype = {
-    tracingComplete: function()
-    {
-        this._asyncEvents.stableSort(WebInspector.TracingModel.Event.compareStartAndEndTime);
-        this._events.stableSort(WebInspector.TracingModel.Event.compareStartTime);
-        var phases = WebInspector.TracingModel.Phase;
-        var stack = [];
-        for (var i = 0; i < this._events.length; ++i) {
-            var e = this._events[i];
-            e.ordinal = i;
-            switch (e.phase) {
-            case phases.End:
-                this._events[i] = null;  // Mark for removal.
-                // Quietly ignore unbalanced close events, they're legit (we could have missed start one).
-                if (!stack.length)
-                    continue;
-                var top = stack.pop();
-                if (top.name !== e.name || top.categoriesString !== e.categoriesString)
-                    console.error("B/E events mismatch at " + top.startTime + " (" + top.name + ") vs. " + e.startTime + " (" + e.name + ")");
-                else
-                    top._complete(e);
-                break;
-            case phases.Begin:
-                stack.push(e);
-                break;
-            }
-        }
-        while (stack.length)
-            stack.pop().setEndTime(this._model.maximumRecordTime());
-        this._events.remove(null, false);
-    },
-
-    /**
-     * @param {!WebInspector.TracingManager.EventPayload} payload
-     * @return {?WebInspector.TracingModel.Event} event
-     */
-    _addEvent: function(payload)
-    {
-        var event = payload.ph === WebInspector.TracingModel.Phase.SnapshotObject
-            ? WebInspector.TracingModel.ObjectSnapshot.fromPayload(payload, this)
-            : WebInspector.TracingModel.Event.fromPayload(payload, this);
-        if (WebInspector.TracingModel.isTopLevelEvent(event)) {
-            // Discard nested "top-level" events.
-            if (this._lastTopLevelEvent && this._lastTopLevelEvent.endTime > event.startTime)
-                return null;
-            this._lastTopLevelEvent = event;
-        }
-        this._events.push(event);
-        return event;
-    },
-
-    /**
-     * @param {!WebInspector.TracingModel.AsyncEvent} asyncEvent
-     */
-    _addAsyncEvent: function(asyncEvent)
-    {
-        this._asyncEvents.push(asyncEvent);
-    },
-
-    /**
-     * @override
-     * @param {string} name
-     */
-    _setName: function(name)
-    {
-        WebInspector.TracingModel.NamedObject.prototype._setName.call(this, name);
-        this._process._setThreadByName(name, this);
-    },
-
-    /**
-     * @return {number}
-     */
-    id: function()
-    {
-        return this._id;
-    },
-
-    /**
-     * @return {!WebInspector.TracingModel.Process}
-     */
-    process: function()
-    {
-        return this._process;
-    },
-
-    /**
-     * @return {!Array.<!WebInspector.TracingModel.Event>}
-     */
-    events: function()
-    {
-        return this._events;
-    },
-
-    /**
-     * @return {!Array.<!WebInspector.TracingModel.AsyncEvent>}
-     */
-    asyncEvents: function()
-    {
-        return this._asyncEvents;
-    },
-
-    __proto__: WebInspector.TracingModel.NamedObject.prototype
-};
+  }
+
+  tracingComplete() {
+    this._asyncEvents.stableSort(WebInspector.TracingModel.Event.compareStartAndEndTime);
+    this._events.stableSort(WebInspector.TracingModel.Event.compareStartTime);
+    var phases = WebInspector.TracingModel.Phase;
+    var stack = [];
+    for (var i = 0; i < this._events.length; ++i) {
+      var e = this._events[i];
+      e.ordinal = i;
+      switch (e.phase) {
+        case phases.End:
+          this._events[i] = null;  // Mark for removal.
+          // Quietly ignore unbalanced close events, they're legit (we could have missed start one).
+          if (!stack.length)
+            continue;
+          var top = stack.pop();
+          if (top.name !== e.name || top.categoriesString !== e.categoriesString)
+            console.error(
+                'B/E events mismatch at ' + top.startTime + ' (' + top.name + ') vs. ' + e.startTime + ' (' + e.name +
+                ')');
+          else
+            top._complete(e);
+          break;
+        case phases.Begin:
+          stack.push(e);
+          break;
+      }
+    }
+    while (stack.length)
+      stack.pop().setEndTime(this._model.maximumRecordTime());
+    this._events.remove(null, false);
+  }
+
+  /**
+   * @param {!WebInspector.TracingManager.EventPayload} payload
+   * @return {?WebInspector.TracingModel.Event} event
+   */
+  _addEvent(payload) {
+    var event = payload.ph === WebInspector.TracingModel.Phase.SnapshotObject ?
+        WebInspector.TracingModel.ObjectSnapshot.fromPayload(payload, this) :
+        WebInspector.TracingModel.Event.fromPayload(payload, this);
+    if (WebInspector.TracingModel.isTopLevelEvent(event)) {
+      // Discard nested "top-level" events.
+      if (this._lastTopLevelEvent && this._lastTopLevelEvent.endTime > event.startTime)
+        return null;
+      this._lastTopLevelEvent = event;
+    }
+    this._events.push(event);
+    return event;
+  }
+
+  /**
+   * @param {!WebInspector.TracingModel.AsyncEvent} asyncEvent
+   */
+  _addAsyncEvent(asyncEvent) {
+    this._asyncEvents.push(asyncEvent);
+  }
+
+  /**
+   * @override
+   * @param {string} name
+   */
+  _setName(name) {
+    super._setName(name);
+    this._process._setThreadByName(name, this);
+  }
+
+  /**
+   * @return {number}
+   */
+  id() {
+    return this._id;
+  }
+
+  /**
+   * @return {!WebInspector.TracingModel.Process}
+   */
+  process() {
+    return this._process;
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.TracingModel.Event>}
+   */
+  events() {
+    return this._events;
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.TracingModel.AsyncEvent>}
+   */
+  asyncEvents() {
+    return this._asyncEvents;
+  }
+};