bluetooth: show better error messages for services, characteristics and descriptors

third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp

Index: third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
diff --git a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
index cfcd631d0cca6cabcc09bb9e1ecde684298665d4..06b28ec37546367994df235b0e4639168bdc4e2b 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
@@ -48,6 +48,7 @@ DEFINE_TRACE(BluetoothRemoteGATTService) {
 // or with a vector owning the characteristics.
 void BluetoothRemoteGATTService::GetCharacteristicsCallback(
     const String& serviceInstanceId,
+    const String& requestedCharacteristicUUID,
     mojom::blink::WebBluetoothGATTQueryQuantity quantity,
     ScriptPromiseResolver* resolver,
     mojom::blink::WebBluetoothResult result,
@@ -85,7 +86,14 @@ void BluetoothRemoteGATTService::GetCharacteristicsCallback(
     }
     resolver->resolve(gattCharacteristics);
   } else {
-    resolver->reject(BluetoothError::take(resolver, result));
+    if (result == mojom::blink::WebBluetoothResult::CHARACTERISTIC_NOT_FOUND) {
+      resolver->reject(BluetoothError::take(
+          resolver, result, "No Characteristics matching UUID " +
+                                requestedCharacteristicUUID +
+                                " found in Service with UUID " + uuid() + "."));
+    } else {
+      resolver->reject(BluetoothError::take(resolver, result));
+    }
   }
 }
 
@@ -148,8 +156,8 @@ ScriptPromise BluetoothRemoteGATTService::getCharacteristicsImpl(
       m_service->instance_id, quantity, characteristicsUUID,
       convertToBaseCallback(
           WTF::bind(&BluetoothRemoteGATTService::GetCharacteristicsCallback,
-                    wrapPersistent(this), m_service->instance_id, quantity,
-                    wrapPersistent(resolver))));
+                    wrapPersistent(this), m_service->instance_id,
+                    characteristicsUUID, quantity, wrapPersistent(resolver))));
 
   return promise;
 }