Maintain API compatibility with older versions of V8.

src/log.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 59 matching lines @@
 // Collect statistical profiling information (ticks), default is off.  The
 // tick profiler requires code events, so --prof implies --log-code.
 
 // Forward declarations.
 class LogMessageBuilder;
 class Profiler;
 class Semaphore;
 class Ticker;
 class Isolate;
 class PositionsRecorder;
-class CpuProfiler;
 
 #undef LOG
 #define LOG(isolate, Call)                          \
   do {                                              \
     v8::internal::Logger* logger =                  \
         (isolate)->logger();                        \
     if (logger->is_logging())                       \
       logger->Call;                                 \
   } while (false)
 
@@ skipping 456 matching lines @@
 // Class that extracts stack trace, used for profiling.
 class StackTracer : public AllStatic {
  public:
   static void Trace(Isolate* isolate, TickSample* sample);
 };
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_LOG_H_