Revert recent CPU profiler changes because they broke --prof.

src/platform.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 723 matching lines @@
   virtual ~Sampler();
 
   int interval() const { return interval_; }
 
   // Performs stack sampling.
   void SampleStack(TickSample* sample) {
     DoSampleStack(sample);
     IncSamplesTaken();
   }
 
-  // Performs platform-specific stack sampling.
-  void DoSample();
-
   // This method is called for each sampling period with the current
   // program counter.
   virtual void Tick(TickSample* sample) = 0;
 
   // Start and stop sampler.
   void Start();
   void Stop();
 
   // Is the sampler used for profiling?
   bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
@@ skipping 27 matching lines @@
   Atomic32 active_;
   PlatformData* data_;  // Platform specific data.
   int samples_taken_;  // Counts stack samples taken.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_