[tracing] Support ConvertableToTraceFormat argument type.

test/cctest/test-trace-event.cc

Index: test/cctest/test-trace-event.cc
diff --git a/test/cctest/test-trace-event.cc b/test/cctest/test-trace-event.cc
index 190cb4078296a3e919ffa8fbd6c9f73b5791aa54..cc879df04ba3080f3e583f9e204937e9ef9a5d2e 100644
--- a/test/cctest/test-trace-event.cc
+++ b/test/cctest/test-trace-event.cc
@@ -71,11 +71,13 @@ class MockTracingPlatform : public v8::Platform {
 
   void PerformDelayedTask() {}
 
-  uint64_t AddTraceEvent(char phase, const uint8_t* category_enabled_flag,
-                         const char* name, const char* scope, uint64_t id,
-                         uint64_t bind_id, int num_args, const char** arg_names,
-                         const uint8_t* arg_types, const uint64_t* arg_values,
-                         unsigned int flags) override {
+  uint64_t AddTraceEvent(
+      char phase, const uint8_t* category_enabled_flag, const char* name,
+      const char* scope, uint64_t id, uint64_t bind_id, int num_args,
+      const char** arg_names, const uint8_t* arg_types,
+      const uint64_t* arg_values,
+      std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
+      unsigned int flags) override {
     MockTraceObject* to = new MockTraceObject(phase, std::string(name), id,
                                               bind_id, num_args, flags);
     trace_object_list_.Add(to);