Fix the content_browsertests everywhere maybe.

ui/views/widget/desktop_aura/desktop_native_widget_aura.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 "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
 
 #include "base/bind.h"
 #include "ui/aura/client/stacking_client.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/root_window.h"
@@ skipping 265 matching lines @@
 
 void DesktopNativeWidgetAura::SetAccessibleRole(
     ui::AccessibilityTypes::Role role) {
 }
 
 void DesktopNativeWidgetAura::SetAccessibleState(
     ui::AccessibilityTypes::State state) {
 }
 
 void DesktopNativeWidgetAura::InitModalType(ui::ModalType modal_type) {
-  // We should never be asked to create a DesktopNativeWidgetAura that is modal.
-  DCHECK_EQ(ui::MODAL_TYPE_NONE, modal_type);
+  // 99% of the time, we should not be asked to create a
+  // DesktopNativeWidgetAura that is modal. The case where this breaks down is
+  // when there are no browser windows and a background extension tries to
+  // display a simple alert dialog. (This case was masked because we used to
+  // have a hidden RootWindow which was the parent of these modal dialogs; they
+  // weren't displayed to the user.)
 }
 
 gfx::Rect DesktopNativeWidgetAura::GetWindowBoundsInScreen() const {
   return desktop_root_window_host_->GetWindowBoundsInScreen();
 }
 
 gfx::Rect DesktopNativeWidgetAura::GetClientAreaBoundsInScreen() const {
   return desktop_root_window_host_->GetClientAreaBoundsInScreen();
 }
 
@@ skipping 405 matching lines @@
   drop_helper_->OnDragExit();
 }
 
 int DesktopNativeWidgetAura::OnPerformDrop(const ui::DropTargetEvent& event) {
   DCHECK(drop_helper_.get() != NULL);
   return drop_helper_->OnDrop(event.data(), event.location(),
       last_drop_operation_);
 }
 
 }  // namespace views