DevTools: Do not remove custom CPU throttling value.

third_party/WebKit/Source/devtools/front_end/timeline/TimelinePanel.js

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel 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.
@@ skipping 31 matching lines @@
     this.registerRequiredCSS("timeline/timelinePanel.css");
     this.element.addEventListener("contextmenu", this._contextMenu.bind(this), false);
     this._dropTarget = new WebInspector.DropTarget(this.element, [WebInspector.DropTarget.Types.Files, WebInspector.DropTarget.Types.URIList], WebInspector.UIString("Drop timeline file or URL here"), this._handleDrop.bind(this));
 
     this._state = WebInspector.TimelinePanel.State.Idle;
     this._detailsLinkifier = new WebInspector.Linkifier();
     this._windowStartTime = 0;
     this._windowEndTime = Infinity;
     this._millisecondsToRecordAfterLoadEvent = 3000;
     this._toggleRecordAction = /** @type {!WebInspector.Action }*/ (WebInspector.actionRegistry.action("timeline.toggle-recording"));
+    this._customCPUThrottlingRate = 0;
 
     /** @type {!Array<!WebInspector.TimelineModel.Filter>} */
     this._filters = [];
     if (!Runtime.experiments.isEnabled("timelineShowAllEvents")) {
         this._filters.push(WebInspector.TimelineUIUtils.visibleEventsFilter());
         this._filters.push(new WebInspector.ExcludeTopLevelFilter());
     }
 
     // Create models.
     this._tracingModelBackingStorage = new WebInspector.TempFileBackingStorage("tracing");
@@ skipping 368 matching lines @@
             cpuThrottlingCombobox.select(option);
             hasSelection = true;
         }
         var predefinedRates = new Map([
             [1, WebInspector.UIString("No CPU throttling")],
             [2, WebInspector.UIString("High end device (2\xD7 slowdown)")],
             [5, WebInspector.UIString("Low end device (5\xD7 slowdown)")]
         ]);
         for (var rate of predefinedRates)
             addGroupingOption(rate[1], rate[0]);
-        var customRateText = predefinedRates.has(currentRate)
-            ? WebInspector.UIString("Custom rate\u2026")
-            : WebInspector.UIString("Custom rate (%d\xD7 slowdown)", currentRate);
-        addGroupingOption(customRateText, 0);
+        if (this._customCPUThrottlingRate && !predefinedRates.has(this._customCPUThrottlingRate))
+            addGroupingOption(WebInspector.UIString("Custom rate (%d\xD7 slowdown)", this._customCPUThrottlingRate), this._customCPUThrottlingRate);
+        addGroupingOption(WebInspector.UIString("Set custom rate\u2026"), 0);
     },
 
     _prepareToLoadTimeline: function()
     {
         console.assert(this._state === WebInspector.TimelinePanel.State.Idle);
         this._setState(WebInspector.TimelinePanel.State.Loading);
     },
 
     _createFileSelector: function()
     {
@@ skipping 124 matching lines @@
             return;
         var value = this._cpuThrottlingCombobox.selectedOption().value;
         var isLastOption = this._cpuThrottlingCombobox.selectedIndex() === this._cpuThrottlingCombobox.size() - 1;
         this._populateCPUThrottingCombobox();
         var resultPromise = isLastOption
             ? WebInspector.TimelinePanel.CustomCPUThrottlingRateDialog.show(this._cpuThrottlingCombobox.element)
             : Promise.resolve(value);
         resultPromise.then(text => {
             var value = Number.parseFloat(text);
             if (value >= 1) {
+                if (isLastOption)
+                    this._customCPUThrottlingRate = value;
                 this._cpuThrottlingManager.setRate(value);
                 this._populateCPUThrottingCombobox();
             }
         });
     },
 
     /**
      * @param {boolean} enabled
      */
     _setUIControlsEnabled: function(enabled)
@@ skipping 1519 matching lines @@
     _onKeyDown: function(event)
     {
         if (event.keyCode === WebInspector.KeyboardShortcut.Keys.Enter.code) {
             event.preventDefault();
             this._apply();
         }
     },
 
     __proto__: WebInspector.HBox.prototype
 }