Simplify synthetic roots creation in heap snapshot

src/heap-snapshot-generator.h

Index: src/heap-snapshot-generator.h
diff --git a/src/heap-snapshot-generator.h b/src/heap-snapshot-generator.h
index a0d73bfaec1188009e491cfa808de588e93a4ab6..3e4ce71b8ad80bb102092e7368e0380b0ffab577 100644
--- a/src/heap-snapshot-generator.h
+++ b/src/heap-snapshot-generator.h
@@ -100,7 +100,7 @@ class HeapEntry BASE_EMBEDDED {
   Type type() { return static_cast<Type>(type_); }
   const char* name() { return name_; }
   void set_name(const char* name) { name_ = name; }
-  inline SnapshotObjectId id() { return id_; }
+  SnapshotObjectId id() { return id_; }
   size_t self_size() { return self_size_; }
   unsigned trace_node_id() const { return trace_node_id_; }
   INLINE(int index() const);
@@ -154,7 +154,6 @@ class HeapSnapshot {
   size_t RawSnapshotSize() const;
   HeapEntry* root() { return &entries_[root_index_]; }
   HeapEntry* gc_roots() { return &entries_[gc_roots_index_]; }
-  HeapEntry* natives_root() { return &entries_[natives_root_index_]; }
   HeapEntry* gc_subroot(int index) {
     return &entries_[gc_subroot_indexes_[index]];
   }
@@ -171,10 +170,7 @@ class HeapSnapshot {
                       SnapshotObjectId id,
                       size_t size,
                       unsigned trace_node_id);
-  HeapEntry* AddRootEntry();
-  HeapEntry* AddGcRootsEntry();
-  HeapEntry* AddGcSubrootEntry(int tag);
-  HeapEntry* AddNativesRootEntry();
+  void AddSyntheticRootEntries();
   HeapEntry* GetEntryById(SnapshotObjectId id);
   List<HeapEntry*>* GetSortedEntriesList();
   void FillChildren();
@@ -183,12 +179,15 @@ class HeapSnapshot {
   void PrintEntriesSize();
 
  private:
+  HeapEntry* AddRootEntry();
+  HeapEntry* AddGcRootsEntry();
+  HeapEntry* AddGcSubrootEntry(int tag, SnapshotObjectId id);
+
   HeapProfiler* profiler_;
   const char* title_;
   unsigned uid_;
   int root_index_;
   int gc_roots_index_;
-  int natives_root_index_;
   int gc_subroot_indexes_[VisitorSynchronization::kNumberOfSyncTags];
   List<HeapEntry> entries_;
   List<HeapGraphEdge> edges_;
@@ -223,12 +222,10 @@ class HeapObjectsMap {
   size_t GetUsedMemorySize() const;
 
   SnapshotObjectId GenerateId(v8::RetainedObjectInfo* info);
-  static inline SnapshotObjectId GetNthGcSubrootId(int delta);
 
   static const int kObjectIdStep = 2;
   static const SnapshotObjectId kInternalRootObjectId;
   static const SnapshotObjectId kGcRootsObjectId;
-  static const SnapshotObjectId kNativesRootObjectId;
   static const SnapshotObjectId kGcRootsFirstSubrootId;
   static const SnapshotObjectId kFirstAvailableObjectId;
 
@@ -348,8 +345,6 @@ class V8HeapExplorer : public HeapEntriesAllocator {
 
   static String* GetConstructorName(JSObject* object);
 
-  static HeapObject* const kInternalRootObject;
-
  private:
   typedef bool (V8HeapExplorer::*ExtractReferencesMethod)(int entry,
                                                           HeapObject* object);
@@ -450,9 +445,6 @@ class V8HeapExplorer : public HeapEntriesAllocator {
 
   HeapEntry* GetEntry(Object* obj);
 
-  static inline HeapObject* GetNthGcSubrootObject(int delta);
-  static inline int GetGcSubrootOrder(HeapObject* subroot);
-
   Heap* heap_;
   HeapSnapshot* snapshot_;
   StringsStorage* names_;
@@ -465,12 +457,7 @@ class V8HeapExplorer : public HeapEntriesAllocator {
   HeapObjectsSet weak_containers_;
   v8::HeapProfiler::ObjectNameResolver* global_object_name_resolver_;
 
-  static HeapObject* const kGcRootsObject;
-  static HeapObject* const kFirstGcSubrootObject;
-  static HeapObject* const kLastGcSubrootObject;
-
   friend class IndexedReferencesExtractor;
-  friend class GcSubrootsEnumerator;
   friend class RootsReferencesExtractor;
 
   DISALLOW_COPY_AND_ASSIGN(V8HeapExplorer);