mac: Add metrics to record Bluetooth availability and capabilities.

chrome/browser/mac/hardware_utility.h

+// Copyright 2014 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_MAC_HARDWARE_UTILITY_H_
+#define CHROME_BROWSER_MAC_HARDWARE_UTILITY_H_
+
+namespace hardware_utility {
+
+// The enum is used in a histogram, so the values must not change.
+enum BluetoothAvailability {
+  BLUETOOTH_NOT_AVAILABLE = 0,
+  BLUETOOTH_AVAILABLE_WITHOUT_LE = 1,
+  BLUETOOTH_AVAILABLE_WITH_LE = 2,
+  BLUETOOTH_AVAILABILITY_COUNT,
+};
+
+// Returns the bluetooth availability of the system's hardware.
+BluetoothAvailability GetBluetoothAvailability();
+
+}  // namespace hardware_utility
+
+#endif  // CHROME_BROWSER_MAC_HARDWARE_UTILITY_H_