Speculative Layout Test fix for inspector/sources/debugger/promise-tracker.html

Source/core/inspector/InspectorDebuggerAgent.cpp

Index: Source/core/inspector/InspectorDebuggerAgent.cpp
diff --git a/Source/core/inspector/InspectorDebuggerAgent.cpp b/Source/core/inspector/InspectorDebuggerAgent.cpp
index 0f1a9c2957aa522446827fd15933b434152511d7..ecde674d0ab600cf23ddb50c1d4e709e0a29f376 100644
--- a/Source/core/inspector/InspectorDebuggerAgent.cpp
+++ b/Source/core/inspector/InspectorDebuggerAgent.cpp
@@ -1183,10 +1183,12 @@ void InspectorDebuggerAgent::disablePromiseTracker(ErrorString*)
     promiseTracker().setEnabled(false);
 }
 
-void InspectorDebuggerAgent::getPromises(ErrorString*, RefPtr<Array<PromiseDetails> >& promises)
+void InspectorDebuggerAgent::getPromises(ErrorString* errorString, RefPtr<Array<PromiseDetails> >& promises)
 {
-    if (!promiseTracker().isEnabled())
+    if (!promiseTracker().isEnabled()) {
+        *errorString = "Promise tracking is disabled";
         return;
+    }
     promises = promiseTracker().promises();
 }