Fix crash when JS alert from background page appears during lock screen

chrome/browser/ui/views/frame/browser_view.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/views/frame/browser_view.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 1537 matching lines @@
 }
 
 bool BrowserView::CanMaximize() const {
   return true;
 }
 
 bool BrowserView::CanActivate() const {
   if (!AppModalDialogQueue::GetInstance()->active_dialog())
     return true;
 
+#if defined(USE_AURA) && defined(OS_CHROMEOS)
+  // On Aura window manager controls all windows so settings focus via PostTask
+  // will make only worse because posted task will keep trying to steal focus.
+  AppModalDialogQueue::GetInstance()->ActivateModalDialog();
+#else
   // If another browser is app modal, flash and activate the modal browser. This
   // has to be done in a post task, otherwise if the user clicked on a window
   // that doesn't have the modal dialog the windows keep trying to get the focus
   // from each other on Windows. http://crbug.com/141650.
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&BrowserView::ActivateAppModalDialog,
                  activate_modal_dialog_factory_.GetWeakPtr()));
+#endif
   return false;
 }
 
 string16 BrowserView::GetWindowTitle() const {
   return browser_->GetWindowTitleForCurrentTab();
 }
 
 string16 BrowserView::GetAccessibleWindowTitle() const {
   if (IsOffTheRecord()) {
     return l10n_util::GetStringFUTF16(
@@ skipping 1184 matching lines @@
     // The +1 in the next line creates a 1-px gap between icon and arrow tip.
     gfx::Point icon_bottom(0, location_icon_view->GetImageBounds().bottom() -
         LocationBarView::kIconInternalPadding + 1);
     ConvertPointToTarget(location_icon_view, this, &icon_bottom);
     gfx::Point infobar_top(0, infobar_container_->GetVerticalOverlap(NULL));
     ConvertPointToTarget(infobar_container_, this, &infobar_top);
     top_arrow_height = infobar_top.y() - icon_bottom.y();
   }
   return top_arrow_height;
 }