Provide named links to code objects in heap snapshot.

src/heap-snapshot-generator.cc

Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index 6d2d8912f1a3bd50b9cd6872b84b7a66a7210787..e3e2df0ed8fa6b94d4cef1283566bf1ffd950f73 100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -894,6 +894,11 @@ class IndexedReferencesExtractor : public ObjectVisitor {
         parent_(parent),
         next_index_(1) {
   }
+  void VisitCodeEntry(Address entry_address) {
+     Code* code = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
+     generator_->SetInternalReference(parent_obj_, parent_, "code", code);
+     generator_->TagObject(code, "(code)");
+  }
   void VisitPointers(Object** start, Object** end) {
     for (Object** p = start; p < end; p++) {
       if (CheckVisitedAndUnmark(p)) continue;