[DevTools] Typed events and event listeners.

third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js

Index: third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js
diff --git a/third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js b/third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js
index 3434b971d435adf9d75b8b55f1f4061ed8e9b4e5..ce6adf4d638d7987720593f4d1a6dd4e16bf1839 100644
--- a/third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js
+++ b/third_party/WebKit/Source/devtools/front_end/persistence/Persistence.js
@@ -4,7 +4,7 @@
 /**
  * @unrestricted
  */
-Persistence.Persistence = class extends Common.Object {
+Persistence.Persistence = class extends Common.ObjectBase {
   /**
    * @param {!Workspace.Workspace} workspace
    * @param {!Bindings.BreakpointManager} breakpointManager
@@ -53,7 +53,8 @@ Persistence.Persistence = class extends Common.Object {
     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 */));
   }
 
   /**
@@ -74,7 +75,8 @@ Persistence.Persistence = class extends Common.Object {
     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 */));
   }
 
   /**
@@ -225,9 +227,17 @@ Persistence.Persistence._NodePrefix = '(function (exports, require, module, __fi
 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;
+  }
 };
 
 /**