Runtime checks so that CoreBluetooth only used on >= 10.10

device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h

Index: device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h
diff --git a/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h b/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h
index c3f707c7fd2c15603296537cb1ae46d5cbf08703..5d396a895b1dd41e6b9f9bbb12cef7ef8638e814 100644
--- a/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h
+++ b/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.h
@@ -80,14 +80,10 @@ class BluetoothLowEnergyDiscoveryManagerMac {
   // Observer interested in notifications from us.
   Observer* observer_;
 
-  // Underlying CoreBluetooth central manager.
-  //
-  // Note: Intentionally leaked. Deallocating CBCentralManager
-  // results in a crash, at least when running OSX 10.9.5 on a
-  // mac_chromuim_rel_ng trybot. On the other hand, restricting |manager_| use
-  // to 10.10 and later would mean the code is unrun and untested by the current
-  // trybots. To work around this we call retain on |manager_| after allocation,
-  // so that the object is leaked.
+  // Underlying CoreBluetooth central manager.  Should only be instantiated on
+  // OS X >= 10.10 as was found to crash on the mac_chromium_rel_ng trybot
+  // running 10.9.5.  May also cause blued to crash on OS X 10.9.5
+  // (crbug.com/506287).
   base::scoped_nsobject<CBCentralManager> manager_;
 
   // Discovery has been initiated by calling the API StartDiscovery().