DevTools: migrate from external Maps to symbols in the bindings objects.

third_party/WebKit/Source/devtools/front_end/components_lazy/LineLevelProfile.js

 // Copyright 2016 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.
 /**
  * @unrestricted
  */
 Components.LineLevelProfile = class {
   constructor() {
     this._locationPool = new Bindings.LiveLocationPool();
     this.reset();
@@ skipping 115 matching lines @@
 Components.LineLevelProfile.LineDecorator = class {
   /**
    * @override
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {!TextEditor.CodeMirrorTextEditor} textEditor
    */
   decorate(uiSourceCode, textEditor) {
     var gutterType = 'CodeMirror-gutter-performance';
     var decorations = uiSourceCode.decorationsForType(Components.LineLevelProfile.LineDecorator.type);
     textEditor.uninstallGutter(gutterType);
-    if (!decorations.size)
+    if (!decorations || !decorations.size)
       return;
     textEditor.installGutter(gutterType, false);
     for (var decoration of decorations) {
       var time = /** @type {number} */ (decoration.data());
       var text = Common.UIString('%.1f\xa0ms', time);
       var intensity = Number.constrain(Math.log10(1 + 2 * time) / 5, 0.02, 1);
       var element = createElementWithClass('div', 'text-editor-line-marker-performance');
       element.textContent = text;
       element.style.backgroundColor = `hsla(44, 100%, 50%, ${intensity.toFixed(3)})`;
       textEditor.setGutterDecoration(decoration.range().startLine, gutterType, element);
     }
   }
 };
 
 Components.LineLevelProfile.LineDecorator.type = 'performance';