[DevTools] Typed events and event listeners.

third_party/WebKit/Source/devtools/front_end/persistence/Persistence.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
  */
-Persistence.Persistence = class extends Common.Object {
+Persistence.Persistence = class extends Common.ObjectBase {
   /**
    * @param {!Workspace.Workspace} workspace
    * @param {!Bindings.BreakpointManager} breakpointManager
    * @param {!Workspace.FileSystemMapping} fileSystemMapping
    */
   constructor(workspace, breakpointManager, fileSystemMapping) {
     super();
     this._workspace = workspace;
     this._breakpointManager = breakpointManager;
     /** @type {!Map<string, number>} */
@@ skipping 28 matching lines @@
     binding.fileSystem.forceLoadOnCheckContent();
 
     binding.network.addEventListener(
         Workspace.UISourceCode.Events.WorkingCopyCommitted, this._onWorkingCopyCommitted, this);
     binding.fileSystem.addEventListener(
         Workspace.UISourceCode.Events.WorkingCopyCommitted, this._onWorkingCopyCommitted, this);
 
     this._addFilePathBindingPrefixes(binding.fileSystem.url());
 
     this._moveBreakpoints(binding.fileSystem, binding.network);
-    this.dispatchEventToListeners(Persistence.Persistence.Events.BindingCreated, binding);
+    this.dispatchEventToListeners(
+        new Persistence.Persistence.BindingChangedEvent(binding, true /* created */, false /* removed */));
   }
 
   /**
    * @param {!Persistence.PersistenceBinding} binding
    */
   _onBindingRemoved(binding) {
     if (binding.network.isDirty())
       binding.fileSystem.setWorkingCopy(binding.network.workingCopy());
 
     binding.network[Persistence.Persistence._binding] = null;
     binding.fileSystem[Persistence.Persistence._binding] = null;
 
     binding.network.removeEventListener(
         Workspace.UISourceCode.Events.WorkingCopyCommitted, this._onWorkingCopyCommitted, this);
     binding.fileSystem.removeEventListener(
         Workspace.UISourceCode.Events.WorkingCopyCommitted, this._onWorkingCopyCommitted, this);
 
     this._removeFilePathBindingPrefixes(binding.fileSystem.url());
 
     this._breakpointManager.copyBreakpoints(binding.network.url(), binding.fileSystem);
-    this.dispatchEventToListeners(Persistence.Persistence.Events.BindingRemoved, binding);
+    this.dispatchEventToListeners(
+        new Persistence.Persistence.BindingChangedEvent(binding, false /* created */, true /* removed */));
   }
 
   /**
    * @param {!Common.Event} event
    */
   _onWorkingCopyCommitted(event) {
     var uiSourceCode = /** @type {!Workspace.UISourceCode} */ (event.target);
     var binding = uiSourceCode[Persistence.Persistence._binding];
     if (!binding || binding[Persistence.Persistence._muteCommit])
       return;
@@ skipping 130 matching lines @@
   }
 };
 
 Persistence.Persistence._binding = Symbol('Persistence.Binding');
 Persistence.Persistence._muteCommit = Symbol('Persistence.MuteCommit');
 
 Persistence.Persistence._NodePrefix = '(function (exports, require, module, __filename, __dirname) { ';
 Persistence.Persistence._NodeSuffix = '\n});';
 Persistence.Persistence._NodeShebang = '#!/usr/bin/env node\n';
 
-Persistence.Persistence.Events = {
-  BindingCreated: Symbol('BindingCreated'),
-  BindingRemoved: Symbol('BindingRemoved')
+Persistence.Persistence.BindingChangedEvent = class {

[pfeldman, 2016/11/28 19:30:38]

"FooEvent" should inherit from "Event" and have properties such as "source",
"target", etc.

+  /**
+   * @param {!Persistence.PersistenceBinding} binding
+   * @param {boolean} created
+   * @param {boolean} removed
+   */
+  constructor(binding, created, removed) {
+    this.binding = binding;
+    this.created = created;
+    this.removed = removed;
+  }
 };
 
 /**
  * @unrestricted
  */
 Persistence.PersistenceBinding = class {
   /**
    * @param {!Workspace.UISourceCode} network
    * @param {!Workspace.UISourceCode} fileSystem
    * @param {boolean} exactMatch
    */
   constructor(network, fileSystem, exactMatch) {
     this.network = network;
     this.fileSystem = fileSystem;
     this.exactMatch = exactMatch;
   }
 };
 
 /** @type {!Persistence.Persistence} */
 Persistence.persistence;