bluetooth: mac: write characteristic implementation

device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm

Index: device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm
diff --git a/device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm b/device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm
index 67880b8cf2ca0c463bbea6c34084233faca97809..487b5134949baa18856c2dfb6cbc8a0e99b2d68d 100644
--- a/device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm
+++ b/device/bluetooth/test/mock_bluetooth_cbperipheral_mac.mm
@@ -96,6 +96,15 @@ using base::scoped_nsobject;
   _bluetoothTestMac->OnFakeBluetoothCharacteristicReadValue();
 }
 
+- (void)writeValue:(NSData*)data
+    forCharacteristic:(CBCharacteristic*)characteristic
+                 type:(CBCharacteristicWriteType)type {
+  DCHECK(_bluetoothTestMac);
+  const uint8_t* buffer = static_cast<const uint8_t*>(data.bytes);
+  std::vector<uint8_t> value(buffer, buffer + data.length);
+  _bluetoothTestMac->OnFakeBluetoothCharacteristicWriteValue(value);
+}
+
 - (void)removeAllServices {
   [_services.get() removeAllObjects];
 }