Split nodes and edges into separate arrays in heap profiler.

src/profile-generator-inl.h

Index: src/profile-generator-inl.h
diff --git a/src/profile-generator-inl.h b/src/profile-generator-inl.h
index 284e2dfa361af19df6f6f8cf159dbb977d612922..9afc52fa080a37d1daf91b130701854c125086b4 100644
--- a/src/profile-generator-inl.h
+++ b/src/profile-generator-inl.h
@@ -96,8 +96,51 @@ CodeEntry* ProfileGenerator::EntryForVMState(StateTag tag) {
 
 
 HeapEntry* HeapGraphEdge::from() const {
-  return const_cast<HeapEntry*>(
-      reinterpret_cast<const HeapEntry*>(this - child_index_) - 1);
+  return &snapshot()->entries()[from_index_];
+}
+
+
+HeapSnapshot* HeapGraphEdge::snapshot() const {
+  return to_entry_->snapshot();
+}
+
+
+int HeapEntry::index() const {
+  return static_cast<int>(this - &snapshot_->entries().first());
+}
+
+
+int HeapEntry::set_children_index(int index) {
+  children_index_ = index;
+  int next_index = index + children_count_;
+  children_count_ = 0;
+  return next_index;
+}
+
+
+int HeapEntry::set_retainers_index(int index) {
+  retainers_index_ = index;
+  int next_index = index + retainers_count_;
+  retainers_count_ = 0;
+  return next_index;
+}
+
+
+HeapGraphEdge** HeapEntry::children_arr() {
+  ASSERT(children_index_ >= 0);
+  return &snapshot_->children()[children_index_];
+}
+
+
+HeapGraphEdge** HeapEntry::retainers_arr() {
+  ASSERT(retainers_index_ >= 0);
+  return &snapshot_->retainers()[retainers_index_];
+}
+
+
+HeapEntry* HeapEntry::dominator() const {
+  ASSERT(dominator_ >= 0);
+  return &snapshot_->entries()[dominator_];
 }