Revert of [DevTools] Remove methods on Common.Event.

third_party/WebKit/Source/devtools/front_end/common/Object.js

Index: third_party/WebKit/Source/devtools/front_end/common/Object.js
diff --git a/third_party/WebKit/Source/devtools/front_end/common/Object.js b/third_party/WebKit/Source/devtools/front_end/common/Object.js
index fe01dd3e28e19a899a215803050bc76d43d93c54..8a308d907cd8188887c5a98b04364598dec39bf0 100644
--- a/third_party/WebKit/Source/devtools/front_end/common/Object.js
+++ b/third_party/WebKit/Source/devtools/front_end/common/Object.js
@@ -87,15 +87,21 @@
    * @override
    * @param {symbol} eventType
    * @param {*=} eventData
+   * @return {boolean}
    */
   dispatchEventToListeners(eventType, eventData) {
     if (!this._listeners || !this._listeners.has(eventType))
-      return;
-
-    var event = new Common.Event(this, eventData);
+      return false;
+
+    var event = new Common.Event(this, eventType, eventData);
     var listeners = this._listeners.get(eventType).slice(0);
-    for (var i = 0; i < listeners.length; ++i)
+    for (var i = 0; i < listeners.length; ++i) {
       listeners[i].listener.call(listeners[i].thisObject, event);
+      if (event._stoppedPropagation)
+        break;
+    }
+
+    return event.defaultPrevented;
   }
 };
 
@@ -105,11 +111,32 @@
 Common.Event = class {
   /**
    * @param {!Common.EventTarget} target
+   * @param {symbol} type
    * @param {*=} data
    */
-  constructor(target, data) {
+  constructor(target, type, data) {
     this.target = target;
+    this.type = type;
     this.data = data;
+    this.defaultPrevented = false;
+    this._stoppedPropagation = false;
+  }
+
+  stopPropagation() {
+    this._stoppedPropagation = true;
+  }
+
+  preventDefault() {
+    this.defaultPrevented = true;
+  }
+
+  /**
+   * @param {boolean=} preventDefault
+   */
+  consume(preventDefault) {
+    this.stopPropagation();
+    if (preventDefault)
+      this.preventDefault();
   }
 };
 
@@ -157,6 +184,7 @@
   /**
    * @param {symbol} eventType
    * @param {*=} eventData
+   * @return {boolean}
    */
   dispatchEventToListeners(eventType, eventData) {},
 };