heap: Switch to non-deprecated APIs

This unblocks fully deprecating the methods that take v8::Value.

Switching Blink to fully use references based on v8::Data is future work.

Bug: v8:9841
Change-Id: I263ae03e9c6057b84fe84bbeff59a0bfbba01c6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1868949
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707294}

third_party/blink/renderer/platform/heap/heap.cc

@@ -585,7 +585,8 @@ void ThreadHeap::FlushV8References() {
       reinterpret_cast<v8::EmbedderHeapTracer*>(
           thread_state_->unified_heap_controller());
   while (v8_references.Pop(&reference)) {
-    controller->RegisterEmbedderReference(reference->Get());
+    controller->RegisterEmbedderReference(
+        reference->template Cast<v8::Data>().Get());
   }
 }
 

third_party/blink/renderer/platform/heap/unified_heap_marking_visitor.cc

@@ -40,7 +40,8 @@ void UnifiedHeapMarkingVisitorBase::VisitImpl(
     v8_references_worklist_.Push(&v8_reference);
     return;
   }
-  controller_->RegisterEmbedderReference(v8_reference.Get());
+  controller_->RegisterEmbedderReference(
+      v8_reference.template Cast<v8::Data>().Get());
 }
 
 UnifiedHeapMarkingVisitor::UnifiedHeapMarkingVisitor(ThreadState* thread_state,