Prevent popunders with the new auto-dismissing dialogs.

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h

Index: chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h
diff --git a/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h b/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h
index dae643be2514cd3533d8953a6bdad7a5db48d331..76c2033be2c93ebad8ef492fd9ba39a2ce27bc7d 100644
--- a/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h
+++ b/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/browser_list_observer.h"
@@ -37,6 +38,8 @@ class JavaScriptDialogTabHelper
   explicit JavaScriptDialogTabHelper(content::WebContents* web_contents);
   ~JavaScriptDialogTabHelper() override;
 
+  void SetDialogShownCallbackForTesting(base::Closure callback);
+
   // JavaScriptDialogManager:
   void RunJavaScriptDialog(content::WebContents* web_contents,
                            const GURL& origin_url,
@@ -76,6 +79,8 @@ class JavaScriptDialogTabHelper
   // user's input but by a call to |CloseDialog|, this class will call it.
   content::JavaScriptDialogManager::DialogClosedCallback dialog_callback_;
 
+  base::Closure dialog_shown_;
+
   DISALLOW_COPY_AND_ASSIGN(JavaScriptDialogTabHelper);
 };