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 1db9949905205f79d758e9f49ce6121aa12bdf6f..725f2b8a6516b749cb7952c43a2a0e36c88ff9a4 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothDevice.h
@@ -19,11 +19,13 @@ namespace blink {
 
 class BluetoothAttributeInstanceMap;
 class BluetoothRemoteGATTCharacteristic;
+class BluetoothRemoteGATTDescriptor;
 class BluetoothRemoteGATTServer;
 class BluetoothRemoteGATTService;
 class ScriptPromiseResolver;
 
 struct WebBluetoothRemoteGATTCharacteristicInit;
+struct WebBluetoothRemoteGATTDescriptorInit;
 struct WebBluetoothRemoteGATTService;
 
 // BluetoothDevice represents a physical bluetooth device in the DOM. See IDL.
@@ -58,6 +60,10 @@ class BluetoothDevice final : public EventTargetWithInlineData,
       BluetoothRemoteGATTService*);
   bool isValidCharacteristic(const String& characteristicInstanceId);
 
+  BluetoothRemoteGATTDescriptor* getOrCreateBluetoothRemoteGATTDescriptor(
+      std::unique_ptr<WebBluetoothRemoteGATTDescriptorInit>,
+      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.