Don't compile with TraceLog support on by default.

base/trace_event.h

 // 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.
 
 // Trace events to track application performance.  Events consist of a name
 // a type (BEGIN, END or INSTANT), a tracking id and extra string data.
 // In addition, the current process id, thread id, a timestamp down to the
 // microsecond and a file and line number of the calling location.
 //
 // The current implementation logs these events into a log file of the form
@@ skipping 11 matching lines @@
 #endif
 
 #include <string>
 
 #include "base/lock.h"
 #include "base/scoped_ptr.h"
 #include "base/singleton.h"
 #include "base/time.h"
 #include "base/timer.h"
 
+#if 1  // Set to 0 to compile with tracing.

[Mark Mentovai, 2009/08/20 01:44:34]

Can we make this something like #ifndef ENABLE_TRACE_EVENT?

+#define TRACE_EVENT_BEGIN(name, id, extra) ((void) 0)
+#define TRACE_EVENT_END(name, id, extra) ((void) 0)
+#define TRACE_EVENT_INSTANT(name, id, extra) ((void) 0)
+
+#else
 // Use the following macros rather than using the TraceLog class directly as the
 // underlying implementation may change in the future.  Here's a sample usage:
 // TRACE_EVENT_BEGIN("v8.run", documentId, scriptLocation);
 // RunScript(script);
 // TRACE_EVENT_END("v8.run", documentId, scriptLocation);
 
 // Record that an event (of name, id) has begun.  All BEGIN events should have
 // corresponding END events with a matching (name, id).
 #define TRACE_EVENT_BEGIN(name, id, extra) \
   Singleton<base::TraceLog>::get()->Trace(name, \
@@ skipping 14 matching lines @@
                                           __LINE__)
 
 // Record that an event (of name, id) with no duration has happened.
 #define TRACE_EVENT_INSTANT(name, id, extra) \
   Singleton<base::TraceLog>::get()->Trace(name, \
                                           base::TraceLog::EVENT_INSTANT, \
                                           reinterpret_cast<const void*>(id), \
                                           extra, \
                                           __FILE__, \
                                           __LINE__)
+#endif

[Mark Mentovai, 2009/08/20 01:44:34]

Put a comment saying what you're ending, whatever you decide to call it.

 
 namespace base {
 class ProcessMetrics;
 }
 
 namespace base {
 
 class TraceLog {
  public:
   enum EventType {
@@ skipping 41 matching lines @@
   FILE* log_file_;
   Lock file_lock_;
   TimeTicks trace_start_time_;
   scoped_ptr<base::ProcessMetrics> process_metrics_;
   RepeatingTimer<TraceLog> timer_;
 };
 
 } // namespace base
 
 #endif // BASE_TRACE_EVENT_H_