Correctly keep track of isolates for microtask execution

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 0c62d74ae835d3206f7712a5c853869eb9d488dd..d85fa40c092391c457b3c51c2864d547ea6f4d7e 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -36,6 +36,7 @@
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/UnionTypesCore.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
+#include "bindings/core/v8/V8PerIsolateData.h"
 #include "bindings/core/v8/WindowProxy.h"
 #include "core/HTMLElementFactory.h"
 #include "core/HTMLNames.h"
@@ -4515,7 +4516,7 @@ void Document::finishedParsing()
     // Ensure Custom Element callbacks are drained before DOMContentLoaded.
     // FIXME: Remove this ad-hoc checkpoint when DOMContentLoaded is dispatched in a
     // queued task, which will do a checkpoint anyway. https://crbug.com/425790
-    Microtask::performCheckpoint();
+    Microtask::performCheckpoint(V8PerIsolateData::mainThreadIsolate());
 
     if (RefPtrWillBeRawPtr<LocalFrame> frame = this->frame()) {
         // Don't update the layout tree if we haven't requested the main resource yet to avoid