[profiler] Implement POC Sampling Heap Profiler

src/api.cc

 // Copyright 2012 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.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 8263 matching lines @@
 }
 
 
 SnapshotObjectId HeapProfiler::GetHeapStats(OutputStream* stream,
                                             int64_t* timestamp_us) {
   i::HeapProfiler* heap_profiler = reinterpret_cast<i::HeapProfiler*>(this);
   return heap_profiler->PushHeapObjectsStats(stream, timestamp_us);
 }
 
 
+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();
+}
+
+
+AllocationProfile HeapProfiler::GetAllocationProfile() {
+  return reinterpret_cast<i::HeapProfiler*>(this)->GetAllocationProfile();
+}
+
+
+AllocationProfile::Node* AllocationProfile::GetRootNode() {
+  return nodes.size() == 0 ? nullptr : &nodes.front();
+}
+
+
 void HeapProfiler::DeleteAllHeapSnapshots() {
   reinterpret_cast<i::HeapProfiler*>(this)->DeleteAllSnapshots();
 }
 
 
 void HeapProfiler::SetWrapperClassInfoProvider(uint16_t class_id,
                                                WrapperInfoCallback callback) {
   reinterpret_cast<i::HeapProfiler*>(this)->DefineWrapperClass(class_id,
                                                                callback);
 }
@@ skipping 243 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8