Expose TickSample and its APIs in v8-profiler.h

src/profiler/circular-queue-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PROFILER_CIRCULAR_QUEUE_INL_H_
 #define V8_PROFILER_CIRCULAR_QUEUE_INL_H_
 
 #include "src/profiler/circular-queue.h"
 
 namespace v8 {
@@ skipping 37 matching lines @@
   return NULL;
 }
 
 
 template<typename T, unsigned L>
 void SamplingCircularQueue<T, L>::FinishEnqueue() {
   base::Release_Store(&enqueue_pos_->marker, kFull);
   enqueue_pos_ = Next(enqueue_pos_);
 }
 
+template <typename T, unsigned L>
+T* SamplingCircularQueue<T, L>::CurrentEnqueue() {
+  base::MemoryBarrier();
+  return &enqueue_pos_->record;
+}
 
 template<typename T, unsigned L>
 typename SamplingCircularQueue<T, L>::Entry* SamplingCircularQueue<T, L>::Next(
     Entry* entry) {
   Entry* next = entry + 1;
   if (next == &buffer_[L]) return buffer_;
   return next;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PROFILER_CIRCULAR_QUEUE_INL_H_