[DevTools] Typed events and event listeners.

third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js

Index: third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js b/third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js
index 58bb873cb68bd03e3662ec4bd30d12d2f6eff771..b2170f6907c36437c197dc710bc615857b07d3a5 100644
--- a/third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/resources/DOMStorageModel.js
@@ -30,7 +30,7 @@
 /**
  * @unrestricted
  */
-Resources.DOMStorage = class extends Common.Object {
+Resources.DOMStorage = class extends Common.ObjectBase {
   /**
    * @param {!Resources.DOMStorageModel} model
    * @param {string} securityOrigin
@@ -90,13 +90,39 @@ Resources.DOMStorage = class extends Common.Object {
   }
 };
 
+Resources.DOMStorage.ItemsClearedEvent = class {};
 
-/** @enum {symbol} */
-Resources.DOMStorage.Events = {
-  DOMStorageItemsCleared: Symbol('DOMStorageItemsCleared'),
-  DOMStorageItemRemoved: Symbol('DOMStorageItemRemoved'),
-  DOMStorageItemAdded: Symbol('DOMStorageItemAdded'),
-  DOMStorageItemUpdated: Symbol('DOMStorageItemUpdated')
+Resources.DOMStorage.ItemRemovedEvent = class {
+  /**
+   * @param {string} key
+   */
+  constructor(key) {
+    this.key = key;
+  }
+};
+
+Resources.DOMStorage.ItemAddedEvent = class {
+  /**
+   * @param {string} key
+   * @param {string} value
+   */
+  constructor(key, value) {
+    this.key = key;
+    this.value = value;
+  }
+};
+
+Resources.DOMStorage.ItemUpdatedEvent = class {
+  /**
+   * @param {string} key
+   * @param {string} oldValue
+   * @param {string} newValue
+   */
+  constructor(key, oldValue, newValue) {
+    this.key = key;
+    this.oldValue = oldValue;
+    this.newValue = newValue;
+  }
 };
 
 /**
@@ -219,9 +245,7 @@ Resources.DOMStorageModel = class extends SDK.SDKModel {
     var domStorage = this.storageForId(storageId);
     if (!domStorage)
       return;
-
-    var eventData = {};
-    domStorage.dispatchEventToListeners(Resources.DOMStorage.Events.DOMStorageItemsCleared, eventData);
+    domStorage.dispatchEventToListeners(new Resources.DOMStorage.ItemsClearedEvent());
   }
 
   /**
@@ -232,9 +256,7 @@ Resources.DOMStorageModel = class extends SDK.SDKModel {
     var domStorage = this.storageForId(storageId);
     if (!domStorage)
       return;
-
-    var eventData = {key: key};
-    domStorage.dispatchEventToListeners(Resources.DOMStorage.Events.DOMStorageItemRemoved, eventData);
+    domStorage.dispatchEventToListeners(new Resources.DOMStorage.ItemRemovedEvent(key));
   }
 
   /**
@@ -246,9 +268,7 @@ Resources.DOMStorageModel = class extends SDK.SDKModel {
     var domStorage = this.storageForId(storageId);
     if (!domStorage)
       return;
-
-    var eventData = {key: key, value: value};
-    domStorage.dispatchEventToListeners(Resources.DOMStorage.Events.DOMStorageItemAdded, eventData);
+    domStorage.dispatchEventToListeners(new Resources.DOMStorage.ItemAddedEvent(key, value));
   }
 
   /**
@@ -261,9 +281,7 @@ Resources.DOMStorageModel = class extends SDK.SDKModel {
     var domStorage = this.storageForId(storageId);
     if (!domStorage)
       return;
-
-    var eventData = {key: key, oldValue: oldValue, value: value};
-    domStorage.dispatchEventToListeners(Resources.DOMStorage.Events.DOMStorageItemUpdated, eventData);
+    domStorage.dispatchEventToListeners(new Resources.DOMStorage.ItemUpdatedEvent(key, oldValue, value));
   }
 
   /**