Bluetooth: mac: Working on macOS descriptor implementation.

device/bluetooth/test/mock_bluetooth_cbdescriptor_mac.mm

+// Copyright 2017 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.
+
+#include "device/bluetooth/test/mock_bluetooth_cbdescriptor_mac.h"
+
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_nsobject.h"
+#include "device/bluetooth/bluetooth_gatt_characteristic.h"
+
+using base::mac::ObjCCast;
+using base::scoped_nsobject;
+
+@interface MockCBDescriptor () {
+  // Owner of this instance.
+  CBCharacteristic* _characteristic;
+  scoped_nsobject<CBUUID> _UUID;
+}
+@end
+
+@implementation MockCBDescriptor
+
+- (instancetype)initWithCharacteristic:(CBCharacteristic*)characteristic
+                                CBUUID:(CBUUID*)uuid {
+  self = [super init];
+  if (self) {
+    _characteristic = characteristic;
+    _UUID.reset([uuid retain]);
+  }
+  return self;
+}
+
+- (BOOL)isKindOfClass:(Class)aClass {
+  if (aClass == [CBDescriptor class] ||
+      [aClass isSubclassOfClass:[CBDescriptor class]]) {
+    return YES;
+  }
+  return [super isKindOfClass:aClass];
+}
+
+- (BOOL)isMemberOfClass:(Class)aClass {
+  if (aClass == [CBDescriptor class] ||
+      [aClass isSubclassOfClass:[CBDescriptor class]]) {
+    return YES;
+  }
+  return [super isKindOfClass:aClass];
+}
+
+- (CBUUID*)UUID {
+  return _UUID.get();
+}
+
+- (CBDescriptor*)descriptor {
+  return ObjCCast<CBDescriptor>(self);
+}
+
+- (CBCharacteristic*)characteristic {
+  return _characteristic;
+}
+
+@end