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

third_party/WebKit/Source/devtools/front_end/main/Main.js

Index: third_party/WebKit/Source/devtools/front_end/main/Main.js
diff --git a/third_party/WebKit/Source/devtools/front_end/main/Main.js b/third_party/WebKit/Source/devtools/front_end/main/Main.js
index 8e59758ff759f9279934c5d687a658abac46fc7a..52c64817f9a209ee4175bee99364f07b786c9b75 100644
--- a/third_party/WebKit/Source/devtools/front_end/main/Main.js
+++ b/third_party/WebKit/Source/devtools/front_end/main/Main.js
@@ -674,7 +674,7 @@
 Main.Main.MainMenuItem = class {
   constructor() {
     this._item = new UI.ToolbarButton(Common.UIString('Customize and control DevTools'), 'largeicon-menu');
-    this._item.addEventListener(UI.ToolbarButton.Events.MouseDown, this._mouseDown, this);
+    this._item.addEventListener('mousedown', this._mouseDown, this);
   }
 
   /**
@@ -706,12 +706,9 @@
       var undock = new UI.ToolbarToggle(Common.UIString('Undock into separate window'), 'largeicon-undock');
       var bottom = new UI.ToolbarToggle(Common.UIString('Dock to bottom'), 'largeicon-dock-to-bottom');
       var right = new UI.ToolbarToggle(Common.UIString('Dock to right'), 'largeicon-dock-to-right');
-      undock.addEventListener(
-          UI.ToolbarButton.Events.MouseUp, setDockSide.bind(null, Components.DockController.State.Undocked));
-      bottom.addEventListener(
-          UI.ToolbarButton.Events.MouseUp, setDockSide.bind(null, Components.DockController.State.DockedToBottom));
-      right.addEventListener(
-          UI.ToolbarButton.Events.MouseUp, setDockSide.bind(null, Components.DockController.State.DockedToRight));
+      undock.addEventListener('mouseup', setDockSide.bind(null, Components.DockController.State.Undocked));
+      bottom.addEventListener('mouseup', setDockSide.bind(null, Components.DockController.State.DockedToBottom));
+      right.addEventListener('mouseup', setDockSide.bind(null, Components.DockController.State.DockedToRight));
       undock.setToggled(Components.dockController.dockSide() === Components.DockController.State.Undocked);
       bottom.setToggled(Components.dockController.dockSide() === Components.DockController.State.DockedToBottom);
       right.setToggled(Components.dockController.dockSide() === Components.DockController.State.DockedToRight);