[DevTools] Remove removeAllListeners method.

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 c25bcda908b940955b8fbebcf936eb2d07b70dee..cf053942051630186538752c734f6ee4ea6fcb5d 100644
--- a/third_party/WebKit/Source/devtools/front_end/common/Object.js
+++ b/third_party/WebKit/Source/devtools/front_end/common/Object.js
@@ -69,13 +69,6 @@ Common.Object = class {
 
   /**
    * @override
-   */
-  removeAllListeners() {
-    delete this._listeners;
-  }
-
-  /**
-   * @override
    * @param {symbol} eventType
    * @return {boolean}
    */
@@ -144,8 +137,6 @@ Common.EventTarget.prototype = {
    */
   removeEventListener(eventType, listener, thisObject) {},
 
-  removeAllListeners() {},
-
   /**
    * @param {symbol} eventType
    * @return {boolean}