Revert "Perform CPU sampling by CPU sampling thread only iff processing thread is not running."

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index 67f6792e1af52ee76d6dd58c16a46afb1a58403e..6f75ca83d5014e82715d1eb76de3a7e09b7449dc 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -753,9 +753,6 @@ class Sampler {
     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;
@@ -764,28 +761,10 @@ class Sampler {
   void Start();
   void Stop();
 
-  // Whether the sampling thread should use this Sampler for CPU profiling?
-  bool IsProfiling() const {
-    return NoBarrier_Load(&profiling_) > 0 &&
-        !NoBarrier_Load(&has_processing_thread_);
-  }
-  // Perform platform-specific initialization before DoSample() may be invoked.
-  void StartSampling();
-  // Perform platform-specific cleanup after samping.
-  void StopSampling();
-  void IncreaseProfilingDepth() {
-    if (NoBarrier_AtomicIncrement(&profiling_, 1) == 1) {
-      StartSampling();
-    }
-  }
-  void DecreaseProfilingDepth() {
-    if (!NoBarrier_AtomicIncrement(&profiling_, -1)) {
-      StopSampling();
-    }
-  }
-  void SetHasProcessingThread(bool value) {
-    NoBarrier_Store(&has_processing_thread_, value);
-  }
+  // Is the sampler used for profiling?
+  bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
+  void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); }
+  void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); }
 
   // Whether the sampler is running (that is, consumes resources).
   bool IsActive() const { return NoBarrier_Load(&active_); }
@@ -812,7 +791,6 @@ class Sampler {
   const int interval_;
   Atomic32 profiling_;
   Atomic32 active_;
-  Atomic32 has_processing_thread_;
   PlatformData* data_;  // Platform specific data.
   int samples_taken_;  // Counts stack samples taken.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);