Expose TickSample and its APIs in v8-profiler.h

src/profiler/circular-queue-inl.h

Index: src/profiler/circular-queue-inl.h
diff --git a/src/profiler/circular-queue-inl.h b/src/profiler/circular-queue-inl.h
index 428945a2eed45a59b2057a91121720db68049c24..7391b459a68feeadd822bbb661f0f33a72493c22 100644
--- a/src/profiler/circular-queue-inl.h
+++ b/src/profiler/circular-queue-inl.h
@@ -55,6 +55,11 @@ void SamplingCircularQueue<T, L>::FinishEnqueue() {
   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(