diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/base/trace_event.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/base/trace_event.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,155 @@
+// Copyright (c) 2006-2008 The Chromium 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 "base/trace_event.h"
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/path_service.h"
+#include "base/platform_thread.h"
+#include "base/process_util.h"
+#include "base/string_util.h"
+#include "base/time.h"
+
+#define USE_UNRELIABLE_NOW
+
+namespace base {
+
+static const char* kEventTypeNames[] = {
+  "BEGIN",
+  "END",
+  "INSTANT"
+};
+
+static const FilePath::CharType* kLogFileName =
+    FILE_PATH_LITERAL("trace_%d.log");
+
+TraceLog::TraceLog() : enabled_(false), log_file_(NULL) {
+  base::ProcessHandle proc = base::GetCurrentProcessHandle();
+  process_metrics_.reset(base::ProcessMetrics::CreateProcessMetrics(proc));
+}
+
+TraceLog::~TraceLog() {
+  Stop();
+}
+
+// static
+bool TraceLog::IsTracing() {
+  TraceLog* trace = Singleton<TraceLog>::get();
+  return trace->enabled_;
+}
+
+// static
+bool TraceLog::StartTracing() {
+  TraceLog* trace = Singleton<TraceLog>::get();
+  return trace->Start();
+}
+
+bool TraceLog::Start() {
+  if (enabled_)
+    return true;
+  enabled_ = OpenLogFile();
+  if (enabled_) {
+    Log("var raw_trace_events = [\n");
+    trace_start_time_ = TimeTicks::Now();
+    timer_.Start(TimeDelta::FromMilliseconds(250), this, &TraceLog::Heartbeat);
+  }
+  return enabled_;
+}
+
+// static
+void TraceLog::StopTracing() {
+  TraceLog* trace = Singleton<TraceLog>::get();
+  return trace->Stop();
+}
+
+void TraceLog::Stop() {
+  if (enabled_) {
+    enabled_ = false;
+    Log("];\n");
+    CloseLogFile();
+    timer_.Stop();
+  }
+}
+
+void TraceLog::Heartbeat() {
+  std::string cpu = StringPrintf("%d", process_metrics_->GetCPUUsage());
+  TRACE_EVENT_INSTANT("heartbeat.cpu", 0, cpu);
+}
+
+void TraceLog::CloseLogFile() {
+  if (log_file_) {
+    file_util::CloseFile(log_file_);
+  }
+}
+
+bool TraceLog::OpenLogFile() {
+  FilePath::StringType pid_filename =
+      StringPrintf(kLogFileName, base::GetCurrentProcId());
+  FilePath log_file_path;
+  if (!PathService::Get(base::DIR_EXE, &log_file_path))
+    return false;
+  log_file_path = log_file_path.Append(pid_filename);
+  log_file_ = file_util::OpenFile(log_file_path, "a");
+  if (!log_file_) {
+    // try the current directory
+    log_file_ = file_util::OpenFile(FilePath(pid_filename), "a");
+    if (!log_file_) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void TraceLog::Trace(const std::string& name,
+                     EventType type,
+                     const void* id,
+                     const std::wstring& extra,
+                     const char* file,
+                     int line) {
+  if (!enabled_)
+    return;
+  Trace(name, type, id, WideToUTF8(extra), file, line);
+}
+
+void TraceLog::Trace(const std::string& name,
+                     EventType type,
+                     const void* id,
+                     const std::string& extra,
+                     const char* file,
+                     int line) {
+  if (!enabled_)
+    return;
+
+#ifdef USE_UNRELIABLE_NOW
+  TimeTicks tick = TimeTicks::HighResNow();
+#else
+  TimeTicks tick = TimeTicks::Now();
+#endif
+  TimeDelta delta = tick - trace_start_time_;
+  int64_t usec = delta.InMicroseconds();
+  std::string msg =
+    StringPrintf("{'pid':'0x%lx', 'tid':'0x%lx', 'type':'%s', "
+                 "'name':'%s', 'id':'0x%lx', 'extra':'%s', 'file':'%s', "
+                 "'line_number':'%d', 'usec_begin': %I64d},\n",
+                 base::GetCurrentProcId(),
+                 PlatformThread::CurrentId(),
+                 kEventTypeNames[type],
+                 name.c_str(),
+                 id,
+                 extra.c_str(),
+                 file,
+                 line,
+                 usec);
+
+  Log(msg);
+}
+
+void TraceLog::Log(const std::string& msg) {
+  AutoLock lock(file_lock_);
+
+  fprintf(log_file_, "%s", msg.c_str());
+}
+
+} // namespace base