Adding unit tests for profiler's stack tracer.

src/log.h

 // Copyright 2006-2008 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 254 matching lines @@
   friend class LogMessageBuilder;
   friend class EventLog;
   friend class TimeLog;
   friend class Profiler;
   friend class SlidingStateWindow;
   friend class VMState;
 #endif
 };
 
 
+// Class that extracts stack trace, used for profiling
+class StackTracer BASE_EMBEDDED {
+ public:
+  StackTracer(unsigned int low_stack_bound): low_stack_bound_(low_stack_bound) {
+  }
+  void Trace(TickSample* sample);
+ private:
+  unsigned int low_stack_bound_;
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_LOG_H_