[Tracing] V8 Tracing Controller - Add args and copy support

src/libplatform/tracing/trace-writer.h

Index: src/libplatform/tracing/trace-writer.h
diff --git a/src/libplatform/tracing/trace-writer.h b/src/libplatform/tracing/trace-writer.h
index d12ed4bffbc3277cfd89e65dca0110539b2a86c4..07bfd1f4d07adc7cc0558e3e816634b9c44223ac 100644
--- a/src/libplatform/tracing/trace-writer.h
+++ b/src/libplatform/tracing/trace-writer.h
@@ -13,12 +13,15 @@ namespace tracing {
 
 class JSONTraceWriter : public TraceWriter {
  public:
-  explicit JSONTraceWriter(std::ostream& stream);
+  JSONTraceWriter(Isolate* isolate, std::ostream& stream);
   ~JSONTraceWriter();
   void AppendTraceEvent(TraceObject* trace_event) override;
   void Flush() override;
 
  private:
+  void AppendTraceValue(uint8_t type, TraceObject::TraceValue value);
+
+  Isolate* isolate_;
   std::ostream& stream_;
   bool append_comma_ = false;
 };