Implement WebContentsView::GetDropData for Mac; disable on Aura

chrome/browser/resources/extensions/extensions.js

Index: chrome/browser/resources/extensions/extensions.js
diff --git a/chrome/browser/resources/extensions/extensions.js b/chrome/browser/resources/extensions/extensions.js
index aedeb4aff2ca2a67ab18c68bb5e36fe4d5366740..b379baa201797f11079b1128c90839fa398c3f58 100644
--- a/chrome/browser/resources/extensions/extensions.js
+++ b/chrome/browser/resources/extensions/extensions.js
@@ -94,8 +94,8 @@ cr.define('extensions', function() {
           this.handleUpdateExtensionNow_.bind(this));
 
       if (!loadTimeData.getBoolean('offStoreInstallEnabled')) {
-        this.dragWrapper_ =
-            new cr.ui.DragWrapper(document.body, dragWrapperHandler);
+        this.dragWrapper_ = new cr.ui.DragWrapper(document.documentElement,
+                                                  dragWrapperHandler);
       }
 
       var packExtensionOverlay = extensions.PackExtensionOverlay.getInstance();