Add UMA for the number of devices in the chooser when a device is paired

chrome/browser/ui/bluetooth/chrome_extension_bluetooth_chooser.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_BLUETOOTH_CHROME_EXTENSION_BLUETOOTH_CHOOSER_H_
 #define CHROME_BROWSER_UI_BLUETOOTH_CHROME_EXTENSION_BLUETOOTH_CHOOSER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "content/public/browser/bluetooth_chooser.h"
 
 class BluetoothChooserController;
 class ChromeExtensionChooserDialog;
 
 namespace content {
 class RenderFrameHost;
 }
 
 // Represents a Bluetooth chooser to ask the user to select a Bluetooth
 // device from a list of options. This implementation is for extensions.
 class ChromeExtensionBluetoothChooser : public content::BluetoothChooser {
  public:
   ChromeExtensionBluetoothChooser(
       content::RenderFrameHost* frame,
-      const content::BluetoothChooser::EventHandler& event_handler);
+      const content::BluetoothChooser::EventHandler& event_handler,
+      bool accept_all_devices);
   ~ChromeExtensionBluetoothChooser() override;
 
   // content::BluetoothChooser:
   void SetAdapterPresence(AdapterPresence presence) override;
   void ShowDiscoveryState(DiscoveryState state) override;
   void AddOrUpdateDevice(const std::string& device_id,
                          bool should_update_name,
                          const base::string16& device_name,
                          bool is_gatt_connected,
                          bool is_paired,
                          int signal_strength_level) override;
   void RemoveDevice(const std::string& device_id) override;
 
  private:
   // Weak. ChooserContentView[Cocoa] owns it.
   BluetoothChooserController* bluetooth_chooser_controller_;
   std::unique_ptr<ChromeExtensionChooserDialog> chooser_dialog_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeExtensionBluetoothChooser);
 };
 
 #endif  // CHROME_BROWSER_UI_BLUETOOTH_CHROME_EXTENSION_BLUETOOTH_CHOOSER_H_