Don't attempt to show validation bubble for unparented web contents.

chrome/browser/ui/browser.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 1242 matching lines @@
 bool Browser::TabsNeedBeforeUnloadFired() {
   if (IsFastTabUnloadEnabled())
     return fast_unload_controller_->TabsNeedBeforeUnloadFired();
   return unload_controller_->TabsNeedBeforeUnloadFired();
 }
 
 void Browser::ShowValidationMessage(content::WebContents* web_contents,
                                     const gfx::Rect& anchor_in_root_view,
                                     const base::string16& main_text,
                                     const base::string16& sub_text) {
+  // If the web contents is unparented (e.g. in a blocked popup) it does not
+  // make sense to show a validation message. See http://crbug.com/616990
+  if (!web_contents->GetTopLevelNativeWindow())
+    return;
   validation_message_bubble_ =
       TabDialogs::FromWebContents(web_contents)
           ->ShowValidationMessage(anchor_in_root_view, main_text, sub_text);
 }
 
 void Browser::HideValidationMessage(content::WebContents* web_contents) {
   if (validation_message_bubble_)
     validation_message_bubble_->CloseValidationMessage();
 }
 
@@ skipping 1325 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         ui::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }