mac: Add metrics to record Bluetooth availability and capabilities.

chrome/browser/mac/bluetooth_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_BLUETOOTH_UTILITY_H_
+#define CHROME_BROWSER_MAC_BLUETOOTH_UTILITY_H_
+
+namespace bluetooth_utility {
+
+// The enum is used in a histogram, so the values must not change.
+enum BluetoothAvailability {
+  BLUETOOTH_AVAILABILITY_ERROR = 0,  // Error determining availability.
+  BLUETOOTH_NOT_AVAILABLE = 1,
+  BLUETOOTH_AVAILABLE_WITHOUT_LE = 2,
+  BLUETOOTH_AVAILABLE_WITH_LE = 3,
+
+  // On OSX 10.6, if the LMP version supports LE, there is no further

[Ilya Sherman, 2014/07/11 19:03:51]

nit: Probably worth spelling out the acronym "LMP", so that somebody trying to
learn about the relevant concepts has a better chance of finding hits.

[erikchen, 2014/07/11 20:34:38]

Done.

+  // indication of whether LE is supported.
+  BLUETOOTH_AVAILABLE_LE_UNKNOWN = 4,
+  BLUETOOTH_AVAILABILITY_COUNT,
+};
+
+// Returns the bluetooth availability of the system's hardware.
+BluetoothAvailability GetBluetoothAvailability();
+
+}  // namespace bluetooth_utility
+
+#endif  // CHROME_BROWSER_MAC_BLUETOOTH_UTILITY_H_