Add support for ES6 Symbol in heap profiler

src/heap-snapshot-generator.h

 // Copyright 2013 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_HEAP_SNAPSHOT_GENERATOR_H_
 #define V8_HEAP_SNAPSHOT_GENERATOR_H_
 
 #include "profile-generator-inl.h"
 
 namespace v8 {
@@ skipping 65 matching lines @@
     kArray = v8::HeapGraphNode::kArray,
     kString = v8::HeapGraphNode::kString,
     kObject = v8::HeapGraphNode::kObject,
     kCode = v8::HeapGraphNode::kCode,
     kClosure = v8::HeapGraphNode::kClosure,
     kRegExp = v8::HeapGraphNode::kRegExp,
     kHeapNumber = v8::HeapGraphNode::kHeapNumber,
     kNative = v8::HeapGraphNode::kNative,
     kSynthetic = v8::HeapGraphNode::kSynthetic,
     kConsString = v8::HeapGraphNode::kConsString,
-    kSlicedString = v8::HeapGraphNode::kSlicedString
+    kSlicedString = v8::HeapGraphNode::kSlicedString,
+    kSymbol = v8::HeapGraphNode::kSymbol
   };
   static const int kNoEntry;
 
   HeapEntry() { }
   HeapEntry(HeapSnapshot* snapshot,
             Type type,
             const char* name,
             SnapshotObjectId id,
             size_t self_size,
             unsigned trace_node_id);
@@ skipping 264 matching lines @@
   const char* GetSystemEntryName(HeapObject* object);
 
   template<V8HeapExplorer::ExtractReferencesMethod extractor>
   bool IterateAndExtractSinglePass();
 
   bool ExtractReferencesPass1(int entry, HeapObject* obj);
   bool ExtractReferencesPass2(int entry, HeapObject* obj);
   void ExtractJSGlobalProxyReferences(int entry, JSGlobalProxy* proxy);
   void ExtractJSObjectReferences(int entry, JSObject* js_obj);
   void ExtractStringReferences(int entry, String* obj);
+  void ExtractSymbolReferences(int entry, Symbol* symbol);
   void ExtractContextReferences(int entry, Context* context);
   void ExtractMapReferences(int entry, Map* map);
   void ExtractSharedFunctionInfoReferences(int entry,
                                            SharedFunctionInfo* shared);
   void ExtractScriptReferences(int entry, Script* script);
   void ExtractAccessorPairReferences(int entry, AccessorPair* accessors);
   void ExtractCodeCacheReferences(int entry, CodeCache* code_cache);
   void ExtractCodeReferences(int entry, Code* code);
   void ExtractBoxReferences(int entry, Box* box);
   void ExtractCellReferences(int entry, Cell* cell);
@@ skipping 231 matching lines @@
   friend class HeapSnapshotJSONSerializerEnumerator;
   friend class HeapSnapshotJSONSerializerIterator;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotJSONSerializer);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_SNAPSHOT_GENERATOR_H_