Address some TODOs for ChooserBubbleDelegate class

chrome/browser/ui/bluetooth/bluetooth_chooser_bubble_delegate.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_UI_BLUETOOTH_BLUETOOTH_CHOOSER_BUBBLE_DELEGATE_H_
 #define CHROME_BROWSER_UI_BLUETOOTH_BLUETOOTH_CHOOSER_BUBBLE_DELEGATE_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "chrome/browser/ui/website_settings/chooser_bubble_delegate.h"
 #include "components/bubble/bubble_reference.h"
 
 class Browser;
 class BluetoothChooserDesktop;
 
 // BluetoothChooserBubbleDelegate is a chooser that presents a list of
 // Bluetooth device names, which come from |bluetooth_chooser_desktop_|.
 // It can be used by WebBluetooth API to get the user's permission to
 // access a Bluetooth device.
 class BluetoothChooserBubbleDelegate : public ChooserBubbleDelegate {
  public:
   explicit BluetoothChooserBubbleDelegate(Browser* browser);
   ~BluetoothChooserBubbleDelegate() override;
 
   // ChooserBubbleDelegate:
-  const std::vector<base::string16>& GetOptions() const override;
-  void Select(int index) override;
+  size_t NumOptions() const override;
+  const base::string16& GetOption(size_t index) const override;
+  void Select(size_t index) override;
   void Cancel() override;
   void Close() override;
 
   // Shows a new device in the chooser.
   void AddDevice(const std::string& device_id,
                  const base::string16& device_name);
 
   // Tells the chooser that a device is no longer available.
   void RemoveDevice(const std::string& device_id);
 
   void set_bluetooth_chooser(BluetoothChooserDesktop* bluetooth_chooser) {
     bluetooth_chooser_ = bluetooth_chooser;
   }
 
   void set_bubble_controller(BubbleReference bubble_controller) {
     bubble_controller_ = bubble_controller;
   }
 
  private:
-  // TODO(juncai): use std::vector<std::pair<base::string16, std::string>>
-  // here since the lengths can't get out of sync and each pair of items
-  // is tightly associated.
-  // Also need to change ChooserBubbleDelegate::GetOptions to be:
-  // size_t NumOptions()
-  // const base::string16& GetOption(size_t index)
-  //
-  // |device_names_| and |device_ids_| have the same length.
-  // device_names_[i] is the name for the device with id device_ids_[i].
-  std::vector<base::string16> device_names_;
-  std::vector<std::string> device_ids_;
+  // Each pair is a (device name, device id).
+  std::vector<std::pair<base::string16, std::string>> device_names_and_ids_;
   BluetoothChooserDesktop* bluetooth_chooser_;
   BubbleReference bubble_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothChooserBubbleDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_BLUETOOTH_BLUETOOTH_CHOOSER_BUBBLE_DELEGATE_H_