bluetooth: Better disconnected error messages for characteristic retrieval.

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

 // Copyright 2014 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.
 
 #ifndef BluetoothError_h
 #define BluetoothError_h
 
 #include "platform/heap/Handle.h"
 #include "third_party/WebKit/public/platform/modules/bluetooth/web_bluetooth.mojom-blink.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
+// Used when generating DOMExceptions specific to each operation.
+// TODO(crbug.com/684445): Add DescriptorsRetrieval and GATTOperation.
+enum class BluetoothOperation {
+  ServicesRetrieval,
+  CharacteristicsRetrieval,
+};
+
 // These error codes requires detailed error messages.
 enum class BluetoothErrorCode {
   InvalidService,
   InvalidCharacteristic,
   InvalidDescriptor,
   ServiceNotFound,
   CharacteristicNotFound,
   DescriptorNotFound
 };
 
 class DOMException;
 
 // BluetoothError is used with CallbackPromiseAdapter to receive
 // WebBluetoothResult responses. See CallbackPromiseAdapter class comments.
 class BluetoothError {
   STATIC_ONLY(BluetoothError);
 
  public:
+  static DOMException* createNotConnectedException(BluetoothOperation);
   static DOMException* createDOMException(BluetoothErrorCode,
                                           const String& detailedMessage);
 
   static DOMException* createDOMException(
       mojom::blink::WebBluetoothResult error);
 };
 
 }  // namespace blink
 
 #endif  // BluetoothError_h