Fix the content_browsertests everywhere maybe.

chrome/browser/ui/app_modal_dialogs/javascript_app_modal_dialog.cc

 // Copyright (c) 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/app_modal_dialogs/javascript_app_modal_dialog.h"
 
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/ui/app_modal_dialogs/native_app_modal_dialog.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #include "ui/base/text/text_elider.h"
 
+#if defined(USE_AURA)
+#include "ui/aura/root_window.h"
+#endif
+
 using content::JavaScriptDialogCreator;
 using content::WebContents;
 
 namespace {
 
 // Control maximum sizes of various texts passed to us from javascript.
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 // Two-dimensional eliding.  Reformat the text of the message dialog
 // inserting line breaks because otherwise a single long line can overflow
 // the message dialog (and crash/hang the GTK, depending on the version).
@@ skipping 50 matching lines @@
   EnforceMaxTextSize(message_text, &message_text_);
   EnforceMaxPromptSize(default_prompt_text, &default_prompt_text_);
 }
 
 JavaScriptAppModalDialog::~JavaScriptAppModalDialog() {
 }
 
 NativeAppModalDialog* JavaScriptAppModalDialog::CreateNativeDialog() {
   gfx::NativeWindow parent_window =
       web_contents()->GetView()->GetTopLevelNativeWindow();
+#if defined(USE_AURA)
+  if (!parent_window->GetRootWindow()) {
+    // When we are part of a WebContents that isn't actually being displayed on

[Ben Goodger (Google), 2013/01/15 18:19:52]

Does this happen when a js alert happens before a WC is parented even to the
hidden root window?

[Elliot Glaysher, 2013/01/15 19:27:51]

Which hidden root window? AFAIK, there never was one in pure ash builds, and
it's being removed in this patch on the desktop; the hidden root window is part
of the DesktopStackingClient.

+    // the screen, we can't actually attach to it.
+    parent_window = NULL;
+  }
+#endif
   return NativeAppModalDialog::CreateNativeJavaScriptPrompt(this,
                                                             parent_window);
 }
 
 bool JavaScriptAppModalDialog::IsJavaScriptModalDialog() {
   return true;
 }
 
 void JavaScriptAppModalDialog::Invalidate() {
   if (!valid_)
@@ skipping 51 matching lines @@
 
   callback_.Run(success, user_input);
 
   extra_data_->last_javascript_message_dismissal_ = base::TimeTicks::Now();
   extra_data_->suppress_javascript_messages_ = suppress_js_messages;
 
   // On Views, we can end up coming through this code path twice :(.
   // See crbug.com/63732.
   valid_ = false;
 }