Reland of [DevTools] Show icon in top toolbar when Node target is available

third_party/WebKit/Source/devtools/front_end/sources/ThreadsSidebarPane.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.
 /**
  * @implements {SDK.SDKModelObserver<!SDK.DebuggerModel>}
  * @implements {UI.ListDelegate<!SDK.DebuggerModel>}
  */
 Sources.ThreadsSidebarPane = class extends UI.VBox {
   constructor() {
     super(true);
     this.registerRequiredCSS('sources/threadsSidebarPane.css');
 
     /** @type {!UI.ListControl<!SDK.DebuggerModel>} */
     this._list = new UI.ListControl(this, UI.ListMode.NonViewport);
     this.contentElement.appendChild(this._list.element);
 
-    this._availableNodeTargetsElement = this.contentElement.createChild('div', 'hidden available-node-targets');
-
     UI.context.addFlavorChangeListener(SDK.Target, this._targetFlavorChanged, this);
-
-    SDK.targetManager.addEventListener(
-        SDK.TargetManager.Events.AvailableNodeTargetsChanged, this._availableNodeTargetsChanged, this);
-    this._availableNodeTargetsChanged();
-
     SDK.targetManager.observeModels(SDK.DebuggerModel, this);
   }
 
   /**
    * @return {boolean}
    */
   static shouldBeShown() {
     var minJSTargets = Runtime.queryParam('nodeFrontend') ? 1 : 2;
-    if (SDK.targetManager.models(SDK.DebuggerModel).length >= minJSTargets)
-      return true;
-    return !!SDK.targetManager.availableNodeTargetsCount();
-  }
-
-  _availableNodeTargetsChanged() {
-    var count = SDK.targetManager.availableNodeTargetsCount();
-    if (!count) {
-      this._availableNodeTargetsElement.classList.add('hidden');
-      return;
-    }
-    this._availableNodeTargetsElement.removeChildren();
-    this._availableNodeTargetsElement.createTextChild(
-        count === 1 ? Common.UIString('Node instance available.') :
-                      Common.UIString('%d Node instances available.', count));
-    var link = this._availableNodeTargetsElement.createChild('span', 'link');
-    link.textContent = Common.UIString('Connect');
-    link.addEventListener('click', () => {
-      InspectorFrontendHost.openNodeFrontend();
-    }, false);
-    this._availableNodeTargetsElement.classList.remove('hidden');
+    return SDK.targetManager.models(SDK.DebuggerModel).length >= minJSTargets;
   }
 
   /**
    * @override
    * @param {!SDK.DebuggerModel} debuggerModel
    * @return {!Element}
    */
   createElementForItem(debuggerModel) {
     var element = createElementWithClass('div', 'thread-item');
     var title = element.createChild('div', 'thread-item-title');
@@ skipping 86 matching lines @@
   /**
    * @param {!Common.Event} event
    */
   _targetFlavorChanged(event) {
     var target = /** @type {!SDK.Target} */ (event.data);
     var debuggerModel = target.model(SDK.DebuggerModel);
     if (debuggerModel)
       this._list.selectItem(debuggerModel);
   }
 };