[profiler] Implement POC Sampling Heap Profiler

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 8ff302f8d82702fa40c471082186a28ed91c8e90..49653a28503ab6a101f19a5cfea5d8475150212b 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -8281,6 +8281,23 @@ SnapshotObjectId HeapProfiler::GetHeapStats(OutputStream* stream,
 }
 
 
+bool HeapProfiler::StartSamplingHeapProfiler(uint64_t sample_interval,
+                                             int stack_depth) {
+  return reinterpret_cast<i::HeapProfiler*>(this)
+      ->StartSamplingHeapProfiler(sample_interval, stack_depth);
+}
+
+
+void HeapProfiler::StopSamplingHeapProfiler() {
+  reinterpret_cast<i::HeapProfiler*>(this)->StopSamplingHeapProfiler();
+}
+
+
+void HeapProfiler::GetHeapSample(OutputStream* stream) {
+  reinterpret_cast<i::HeapProfiler*>(this)->GetHeapSample(stream);
+}
+
+
 void HeapProfiler::DeleteAllHeapSnapshots() {
   reinterpret_cast<i::HeapProfiler*>(this)->DeleteAllSnapshots();
 }