bluetooth: web: Include the UUID in the error message.

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 84d915fd495db3acdbbf855b6811c19d87763f45..16884e8e224026979a886f1bba941e6d08309538 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp
@@ -50,9 +50,13 @@ class GetCharacteristicsCallback
  public:
   GetCharacteristicsCallback(
       BluetoothRemoteGATTService* service,
+      const String characteristicsUUID,
       mojom::blink::WebBluetoothGATTQueryQuantity quantity,
       ScriptPromiseResolver* resolver)
-      : m_service(service), m_quantity(quantity), m_resolver(resolver) {
+      : m_service(service),
+        m_characteristicsUUID(characteristicsUUID),
+        m_quantity(quantity),
+        m_resolver(resolver) {
     // We always check that the device is connected before constructing this
     // object.
     CHECK(m_service->device()->gatt()->connected());
@@ -111,12 +115,22 @@ class GetCharacteristicsCallback
           DOMException::create(NetworkError, kGATTServerDisconnected));
       return;
     }
-
-    m_resolver->reject(BluetoothError::take(m_resolver, error));
+    if (!m_characteristicsUUID.isEmpty() &&
+        BluetoothError::isSameError(
+            error,
+            mojom::blink::WebBluetoothResult::CHARACTERISTIC_NOT_FOUND)) {
+      m_resolver->reject(BluetoothError::take(
+          m_resolver, error,
+          "No Characteristics matching UUID " + m_characteristicsUUID +
+              " found in Service with UUID " + m_service->uuid() + "."));
+    } else {
+      m_resolver->reject(BluetoothError::take(m_resolver, error));
+    }
   }
 
  private:
   Persistent<BluetoothRemoteGATTService> m_service;
+  const String m_characteristicsUUID;
   mojom::blink::WebBluetoothGATTQueryQuantity m_quantity;
   const Persistent<ScriptPromiseResolver> m_resolver;
 };
@@ -178,8 +192,8 @@ ScriptPromise BluetoothRemoteGATTService::getCharacteristicsImpl(
       BluetoothSupplement::fromScriptState(scriptState);
   webbluetooth->getCharacteristics(
       m_webService->serviceInstanceID, static_cast<int32_t>(quantity),
-      characteristicsUUID,
-      new GetCharacteristicsCallback(this, quantity, resolver));
+      characteristicsUUID, new GetCharacteristicsCallback(
+                               this, characteristicsUUID, quantity, resolver));
 
   return promise;
 }