Revert of [debugger api] remove legacy JSON debug protocol.

src/log.cc

 // Copyright 2011 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 "src/log.h"
 
 #include <cstdarg>
 #include <memory>
 #include <sstream>
 
@@ skipping 1231 matching lines @@
 
 
 void Logger::HeapSampleItemEvent(const char* type, int number, int bytes) {
   if (!log_->IsEnabled() || !FLAG_log_gc) return;
   Log::MessageBuilder msg(log_);
   msg.Append("heap-sample-item,%s,%d,%d", type, number, bytes);
   msg.WriteToLogFile();
 }
 
 
+void Logger::DebugTag(const char* call_site_tag) {
+  if (!log_->IsEnabled() || !FLAG_log) return;
+  Log::MessageBuilder msg(log_);
+  msg.Append("debug-tag,%s", call_site_tag);
+  msg.WriteToLogFile();
+}
+
+
+void Logger::DebugEvent(const char* event_type, Vector<uint16_t> parameter) {
+  if (!log_->IsEnabled() || !FLAG_log) return;
+  StringBuilder s(parameter.length() + 1);
+  for (int i = 0; i < parameter.length(); ++i) {
+    s.AddCharacter(static_cast<char>(parameter[i]));
+  }
+  char* parameter_string = s.Finalize();
+  Log::MessageBuilder msg(log_);
+  msg.Append("debug-queue-event,%s,%15.3f,%s", event_type,
+             base::OS::TimeCurrentMillis(), parameter_string);
+  DeleteArray(parameter_string);
+  msg.WriteToLogFile();
+}
+
 void Logger::RuntimeCallTimerEvent() {
   RuntimeCallStats* stats = isolate_->counters()->runtime_call_stats();
   RuntimeCallTimer* timer = stats->current_timer();
   if (timer == nullptr) return;
   RuntimeCallCounter* counter = timer->counter();
   if (counter == nullptr) return;
   Log::MessageBuilder msg(log_);
   msg.Append("active-runtime-timer,");
   msg.AppendDoubleQuotedString(counter->name());
   msg.WriteToLogFile();
@@ skipping 513 matching lines @@
 
   if (profiler_listener_.get() != nullptr) {
     removeCodeEventListener(profiler_listener_.get());
   }
 
   return log_->Close();
 }
 
 }  // namespace internal
 }  // namespace v8