[DevTools] Introduce typed events.

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

Index: third_party/WebKit/Source/devtools/front_end/resources/DatabaseModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/resources/DatabaseModel.js b/third_party/WebKit/Source/devtools/front_end/resources/DatabaseModel.js
index 382e9da89b10134745433c5bea7dff005fa8b601..361e01ecae984f0cdc5bb334ef3ca571363450ff 100644
--- a/third_party/WebKit/Source/devtools/front_end/resources/DatabaseModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/resources/DatabaseModel.js
@@ -164,7 +164,7 @@ Resources.DatabaseModel = class extends SDK.SDKModel {
     this._enabled = false;
     this._databases = [];
     this._agent.disable();
-    this.dispatchEventToListeners(Resources.DatabaseModel.Events.DatabasesRemoved);
+    this.emit(new Resources.DatabaseModel.DatabasesRemovedEvent());
   }
 
   /**
@@ -182,16 +182,21 @@ Resources.DatabaseModel = class extends SDK.SDKModel {
    */
   _addDatabase(database) {
     this._databases.push(database);
-    this.dispatchEventToListeners(Resources.DatabaseModel.Events.DatabaseAdded, database);
+    this.emit(new Resources.DatabaseModel.DatabaseAddedEvent(database));
   }
 };
 
-/** @enum {symbol} */
-Resources.DatabaseModel.Events = {
-  DatabaseAdded: Symbol('DatabaseAdded'),
-  DatabasesRemoved: Symbol('DatabasesRemoved')
+Resources.DatabaseModel.DatabaseAddedEvent = class {

[lushnikov, 2016/12/15 04:28:59]

maybe we can keep a list of events - it was extremely convenient

[dgozman, 2016/12/16 04:17:46]

JSCompiler didn't like it :-(

+  /**
+   * @param {!Resources.Database} database
+   */
+  constructor(database) {
+    this.database = database;
+  }
 };
 
+Resources.DatabaseModel.DatabasesRemovedEvent = class {};
+
 /**
  * @implements {Protocol.DatabaseDispatcher}
  * @unrestricted