Implement WebBluetooth getDescriptor[s]

third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h

Index: third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
diff --git a/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h b/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
index a1798b8bba4953588315b1a4c9d89c133f46a932..369d1afe50b49901325dd2b46bc68b18195bc53e 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
@@ -19,6 +19,7 @@ namespace blink {
 class Bluetooth;
 class BluetoothAttributeInstanceMap;
 class BluetoothRemoteGATTCharacteristic;
+class BluetoothRemoteGATTDescriptor;
 class BluetoothRemoteGATTServer;
 class BluetoothRemoteGATTService;
 class ScriptPromiseResolver;
@@ -57,6 +58,10 @@ class BluetoothDevice final : public EventTargetWithInlineData,
       BluetoothRemoteGATTService*);
   bool isValidCharacteristic(const String& characteristicInstanceId);
 
+  BluetoothRemoteGATTDescriptor* getOrCreateBluetoothRemoteGATTDescriptor(
+      mojom::blink::WebBluetoothRemoteGATTDescriptorPtr,
+      BluetoothRemoteGATTCharacteristic*);
+
   // We should disconnect from the device in all of the following cases:
   // 1. When the object gets GarbageCollected e.g. it went out of scope.
   // dispose() is called in this case.