[Tracing] V8 Tracing Controller

src/libplatform/tracing/trace-writer.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 "src/libplatform/tracing/trace-writer.h"
+
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace platform {
+namespace tracing {
+
+JSONTraceWriter::JSONTraceWriter(std::ostream& stream) : stream_(stream) {
+  stream_ << "{\"traceEvents\":[";
+}
+
+JSONTraceWriter::~JSONTraceWriter() { stream_ << "]}"; }
+
+void JSONTraceWriter::AppendTraceEvent(TraceObject* trace_event) {
+  if (append_comma_) stream_ << ",";
+  append_comma_ = true;
+  stream_ << "{\"pid\":" << trace_event->pid()
+          << ",\"tid\":" << trace_event->tid()
+          << ",\"ts\":" << trace_event->ts()
+          << ",\"tts\":" << trace_event->tts() << ",\"ph\":\""
+          << trace_event->phase() << "\",\"cat\":\""
+          << trace_event->category_group() << "\",\"name\":\""
+          << trace_event->name()
+          << "\",\"args\":{},\"dur\":" << trace_event->duration()
+          << ",\"tdur\":" << trace_event->cpu_duration() << "}";
+}
+
+void JSONTraceWriter::Flush() {}
+
+TraceWriter* TraceWriter::CreateJSONTraceWriter(std::ostream& stream) {
+  return new JSONTraceWriter(stream);
+}
+
+}  // namespace tracing
+}  // namespace platform
+}  // namespace v8