Add RAIL tracing category to Chrome tracing.

content/browser/browser_main_loop.cc

 // Copyright (c) 2012 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 "content/browser/browser_main_loop.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 808 matching lines @@
     // previous call for async startup, so we call RunAllTasksNow()
     // unconditionally.
     startup_task_runner_->RunAllTasksNow();
   }
 #else
   startup_task_runner_->RunAllTasksNow();
 #endif
 }
 
 int BrowserMainLoop::CreateThreads() {
-  TRACE_EVENT0("startup", "BrowserMainLoop::CreateThreads");
+  TRACE_EVENT0("startup,rail", "BrowserMainLoop::CreateThreads");
 
   base::Thread::Options io_message_loop_options;
   io_message_loop_options.message_loop_type = base::MessageLoop::TYPE_IO;
   base::Thread::Options ui_message_loop_options;
   ui_message_loop_options.message_loop_type = base::MessageLoop::TYPE_UI;
 
   // Start threads in the order they occur in the BrowserThread::ID
   // enumeration, except for BrowserThread::UI which is the main
   // thread.
   //
@@ skipping 686 matching lines @@
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner =
         audio_thread_->task_runner();
     audio_manager_ = media::AudioManager::Create(std::move(audio_task_runner),
                                                  std::move(worker_task_runner),
                                                  MediaInternals::GetInstance());
   }
   CHECK(audio_manager_);
 }
 
 }  // namespace content