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

third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js

Index: third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js b/third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js
index d8611db33173a02eb3ab09da02a8a5f6cf33e3e4..0b8dbf6c6a79e5fe9438b149e9bf967f0ed58b65 100644
--- a/third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js
+++ b/third_party/WebKit/Source/devtools/front_end/sources/SourcesNavigator.js
@@ -146,8 +146,7 @@
     var toolbar = new UI.Toolbar('navigator-toolbar');
     var title = Common.UIString('Add folder to workspace');
     var addButton = new UI.ToolbarButton(title, 'largeicon-add', title);
-    addButton.addEventListener(
-        UI.ToolbarButton.Events.Click, () => Workspace.isolatedFileSystemManager.addFileSystem());
+    addButton.addEventListener('click', () => Workspace.isolatedFileSystemManager.addFileSystem());
     toolbar.appendToolbarItem(addButton);
     this.element.insertBefore(toolbar.element, this.element.firstChild);
   }
@@ -198,7 +197,7 @@
     super();
     var toolbar = new UI.Toolbar('navigator-toolbar');
     var newButton = new UI.ToolbarButton('', 'largeicon-add', Common.UIString('New Snippet'));
-    newButton.addEventListener(UI.ToolbarButton.Events.Click, this._handleCreateSnippet.bind(this));
+    newButton.addEventListener('click', this._handleCreateSnippet.bind(this));
     toolbar.appendToolbarItem(newButton);
     this.element.insertBefore(toolbar.element, this.element.firstChild);
   }