Get rid or heap allocation in stack sampler to avoid deadlocks.

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 259 matching lines @@
 };
 
 
 // Class that extracts stack trace, used for profiling
 class StackTracer BASE_EMBEDDED {
  public:
   explicit StackTracer(unsigned int low_stack_bound)
       : low_stack_bound_(low_stack_bound) { }
   void Trace(TickSample* sample);
  private:
-  // Maximum number of stack frames to capture
-  static const int kMaxStackFrames = 5;
 
   unsigned int low_stack_bound_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LOG_H_