Bluetooth: mac: Working on macOS descriptor implementation.

device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h

Index: device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h
diff --git a/device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h b/device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h
index 4a4c9255d2483a1969c0dc40dbaa1b0993c37fee..a231970ff569f5ecbef98563b449ad0578834de6 100644
--- a/device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h
+++ b/device/bluetooth/test/mock_bluetooth_cbcharacteristic_mac.h
@@ -13,8 +13,9 @@
 // This class mocks the behavior of a CBCharacteristic.
 @interface MockCBCharacteristic : NSObject
 
-@property(readonly, nonatomic) CBUUID* UUID;
-@property(readonly, nonatomic) CBCharacteristic* characteristic;
+@property(nonatomic, readonly) CBUUID* UUID;
+@property(nonatomic, readonly) CBCharacteristic* characteristic;
+@property(nonatomic, readonly) NSArray* descriptors;
 
 - (instancetype)initWithService:(CBService*)service
                          CBUUID:(CBUUID*)uuid
@@ -26,6 +27,8 @@
 - (void)simulateGattNotifySessionStarted;
 - (void)simulateGattNotifySessionFailedWithError:(NSError*)error;
 - (void)simulateGattCharacteristicChangedWithValue:(NSData*)value;
+- (void)simulateDescriptorWithUUID:(CBUUID*)uuid;
+- (void)discoverDescriptors;
 
 @end