Runtime checks so that CoreBluetooth only used on >= 10.10

device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm

Index: device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm
diff --git a/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm b/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm
index 67cf39126d78272fe44031d099c2fa6886621d84..18830b3efb819af07045ee340ced66a12e71725a 100644
--- a/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm
+++ b/device/bluetooth/bluetooth_low_energy_discovery_manager_mac.mm
@@ -79,13 +79,6 @@ class BluetoothLowEnergyDiscoveryManagerMacDelegate {
 
 BluetoothLowEnergyDiscoveryManagerMac::
     ~BluetoothLowEnergyDiscoveryManagerMac() {
-  // Set the manager's delegate to nil since the object it points to
-  // (|bridge_|) will be deallocated while |manager_| is leaked.
-  if (base::mac::IsOSLionOrLater()) {
-    // CoreBluetooth only available in OSX 10.7 and later.
-    SEL selector = NSSelectorFromString(@"setDelegate:");
-    [manager_ performSelector:selector withObject:nil];
-  }
 }
 
 bool BluetoothLowEnergyDiscoveryManagerMac::IsDiscovering() const {
@@ -121,8 +114,7 @@ void BluetoothLowEnergyDiscoveryManagerMac::TryStartDiscovery() {
     for (auto& service_uuid : services_uuids_) {
       NSString* uuidString =
           base::SysUTF8ToNSString(service_uuid.canonical_value().c_str());
-      Class aClass = NSClassFromString(@"CBUUID");
-      CBUUID* uuid = [aClass UUIDWithString:uuidString];
+      CBUUID* uuid = [CBUUID UUIDWithString:uuidString];
       [services addObject:uuid];
     }
   };
@@ -147,10 +139,9 @@ void BluetoothLowEnergyDiscoveryManagerMac::DiscoveredPeripheral(
 
 void BluetoothLowEnergyDiscoveryManagerMac::SetManagerForTesting(
     CBCentralManager* manager) {
-  // setDelegate is only available in OSX 10.7 and later.
-  CHECK(base::mac::IsOSLionOrLater());
-  SEL selector = NSSelectorFromString(@"setDelegate:");
-  [manager performSelector:selector withObject:bridge_];
+  // For stability we only use CoreBluetooth on OS X >= 10.10.
+  CHECK(base::mac::IsOSYosemiteOrLater());
+  [manager setDelegate:bridge_];
   manager_.reset(manager);
 }
 
@@ -162,17 +153,14 @@ BluetoothLowEnergyDiscoveryManagerMac::Create(Observer* observer) {
 BluetoothLowEnergyDiscoveryManagerMac::BluetoothLowEnergyDiscoveryManagerMac(
     Observer* observer)
     : observer_(observer) {
+  // For stability we only use CoreBluetooth on OS X >= 10.10.  Thus
+  // BluetoothLowEnergyDiscoveryManagerMac should only be instantiated if on >=
+  // 10.10.
+  CHECK(base::mac::IsOSYosemiteOrLater());
   bridge_.reset([[BluetoothLowEnergyDiscoveryManagerMacBridge alloc]
       initWithManager:this]);
-  // Since CoreBluetooth is only available on OS X 10.7 or later, we
-  // instantiate CBCentralManager only for OS X >= 10.7.
-  if (base::mac::IsOSLionOrLater()) {
-    Class aClass = NSClassFromString(@"CBCentralManager");
-    manager_.reset(
-        [[aClass alloc] initWithDelegate:bridge_
-                                   queue:dispatch_get_main_queue()]);
-    // Increment reference count, see comment at declaration.
-    [manager_ retain];
-  }
+  manager_.reset(
+      [[CBCentralManager alloc] initWithDelegate:bridge_
+                                           queue:dispatch_get_main_queue()]);
   discovering_ = false;
 }