mash: Cleanup ash shelf application menu code.

ash/common/shelf/shelf_application_menu_model.cc

+// Copyright 2017 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/shelf/shelf_application_menu_model.h"
+
+#include <stddef.h>
+
+#include <limits>
+#include <utility>
+
+#include "ash/public/cpp/shelf_application_menu_item.h"
+#include "base/metrics/histogram_macros.h"
+
+namespace {
+
+const int kInvalidCommandId = std::numeric_limits<int>::max();
+
+}  // namespace
+
+namespace ash {
+
+ShelfApplicationMenuModel::ShelfApplicationMenuModel(
+    const base::string16& title,
+    ShelfAppMenuItemList items)
+    : ui::SimpleMenuModel(this), items_(std::move(items)) {
+  AddSeparator(ui::SPACING_SEPARATOR);
+  AddItem(kInvalidCommandId, title);
+  AddSeparator(ui::SPACING_SEPARATOR);
+
+  for (size_t i = 0; i < items_.size(); i++) {
+    ShelfApplicationMenuItem* item = items_[i].get();
+    AddItem(i, item->title());
+    if (!item->icon().IsEmpty())
+      SetIcon(GetIndexOfCommandId(i), item->icon());
+  }
+
+  // SimpleMenuModel does not allow two consecutive spacing separator items.
+  // This only occurs in tests; users should not see menus with no |items_|.
+  if (!items_.empty())
+    AddSeparator(ui::SPACING_SEPARATOR);
+}
+
+ShelfApplicationMenuModel::~ShelfApplicationMenuModel() {}
+
+bool ShelfApplicationMenuModel::IsCommandIdChecked(int command_id) const {
+  return false;
+}
+
+bool ShelfApplicationMenuModel::IsCommandIdEnabled(int command_id) const {
+  return command_id >= 0 && static_cast<size_t>(command_id) < items_.size();
+}
+
+void ShelfApplicationMenuModel::ExecuteCommand(int command_id,
+                                               int event_flags) {
+  DCHECK(IsCommandIdEnabled(command_id));
+  items_[command_id]->Execute(event_flags);
+  RecordMenuItemSelectedMetrics(command_id, items_.size());
+}
+
+void ShelfApplicationMenuModel::RecordMenuItemSelectedMetrics(
+    int command_id,
+    int num_menu_items_enabled) {
+  UMA_HISTOGRAM_COUNTS_100("Ash.Shelf.Menu.SelectedMenuItemIndex", command_id);
+  UMA_HISTOGRAM_COUNTS_100("Ash.Shelf.Menu.NumItemsEnabledUponSelection",
+                           num_menu_items_enabled);
+}
+
+}  // namespace ash