Fix opt-in IME menu crash.

ash/common/system/tray/tray_details_view.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 "ash/common/system/tray/tray_details_view.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/system/tray/fixed_sized_scroll_view.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_item.h"
@@ skipping 57 matching lines @@
       scroll_border_(nullptr),
       back_button_(nullptr),
       settings_button_(nullptr) {
   SetLayoutManager(new views::BoxLayout(views::BoxLayout::kVertical, 0, 0, 0));
   set_background(views::Background::CreateSolidBackground(kBackgroundColor));
 }
 
 TrayDetailsView::~TrayDetailsView() {}
 
 void TrayDetailsView::OnViewClicked(views::View* sender) {
-  if (!MaterialDesignController::IsSystemTrayMenuMaterial() &&
+  if (!MaterialDesignController::IsSystemTrayMenuMaterial() && title_row_ &&
       sender == title_row_->content()) {
     TransitionToDefaultView();
     return;
   }
 
   HandleViewClicked(sender);
 }
 
 void TrayDetailsView::ButtonPressed(views::Button* sender,
                                     const ui::Event& event) {
@@ skipping 120 matching lines @@
     if (index < child_count() - 1 && child_at(index + 1) != title_row_)
       scroll_border_->set_visible(true);
     else
       scroll_border_->set_visible(false);
   }
 
   views::View::OnPaintBorder(canvas);
 }
 
 }  // namespace ash