Revert of [tracing] Support ConvertableToTraceFormat argument type.

src/libplatform/tracing/tracing-controller.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdio.h>
 #include <string.h>
 
 #include "include/libplatform/v8-tracing.h"
 
 #include "src/base/platform/mutex.h"
@@ skipping 28 matching lines @@
 v8::base::AtomicWord g_category_index = g_num_builtin_categories;
 
 void TracingController::Initialize(TraceBuffer* trace_buffer) {
   trace_buffer_.reset(trace_buffer);
 }
 
 uint64_t TracingController::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) {
+    const uint64_t* arg_values, unsigned int flags) {
   uint64_t handle;
   TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
   if (trace_object) {
     trace_object->Initialize(phase, category_enabled_flag, name, scope, id,
                              bind_id, num_args, arg_names, arg_types,
-                             arg_values, arg_convertables, flags);
+                             arg_values, flags);
   }
   return handle;
 }
 
 void TracingController::UpdateTraceEventDuration(
     const uint8_t* category_enabled_flag, const char* name, uint64_t handle) {
   TraceObject* trace_object = trace_buffer_->GetEventByHandle(handle);
   if (!trace_object) return;
   trace_object->UpdateDuration();
 }
@@ skipping 102 matching lines @@
   } else {
     category_group_enabled =
         &g_category_group_enabled[g_category_categories_exhausted];
   }
   return category_group_enabled;
 }
 
 }  // namespace tracing
 }  // namespace platform
 }  // namespace v8