[Ash] Use DCHECK in ImeListView::HandleButtonPressed()

ash/system/ime_menu/ime_list_view.cc

 // Copyright 2016 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/system/ime_menu/ime_list_view.h"
 
 #include "ash/resources/grit/ash_resources.h"
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
@@ skipping 291 matching lines @@
   }
 
   if (!should_focus_ime_after_selection_with_keyboard_ ||
       !last_item_selected_with_keyboard_) {
     CloseImeListView();
   }
 }
 
 void ImeListView::HandleButtonPressed(views::Button* sender,
                                       const ui::Event& event) {
-  if (keyboard_status_row_ && sender == keyboard_status_row_->toggle()) {
-    ShellPort::Get()->ToggleIgnoreExternalKeyboard();
-    last_selected_item_id_.clear();
-    last_item_selected_with_keyboard_ = false;
-  }
+  DCHECK_EQ(sender, keyboard_status_row_->toggle());
+
+  ShellPort::Get()->ToggleIgnoreExternalKeyboard();
+  last_selected_item_id_.clear();
+  last_item_selected_with_keyboard_ = false;
 }
 
 void ImeListView::VisibilityChanged(View* starting_from, bool is_visible) {
   if (!is_visible || (should_focus_ime_after_selection_with_keyboard_ &&
                       last_item_selected_with_keyboard_) ||
       !current_ime_view_) {
     return;
   }
 
   scroll_content()->ScrollRectToVisible(current_ime_view_->bounds());
@@ skipping 22 matching lines @@
 ImeListViewTestApi::ImeListViewTestApi(ImeListView* ime_list_view)
     : ime_list_view_(ime_list_view) {}
 
 ImeListViewTestApi::~ImeListViewTestApi() {}
 
 views::View* ImeListViewTestApi::GetToggleView() const {
   return ime_list_view_->keyboard_status_row_->toggle();
 }
 
 }  // namespace ash