Provide named links to code objects in heap snapshot.

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7538 matching lines @@
   i::HeapGraphEdge* edge = ToInternal(this);
   switch (edge->type()) {
     case i::HeapGraphEdge::kContextVariable:
     case i::HeapGraphEdge::kInternal:
     case i::HeapGraphEdge::kProperty:
     case i::HeapGraphEdge::kShortcut:
       return ToApiHandle<String>(
           isolate->factory()->InternalizeUtf8String(edge->name()));
     case i::HeapGraphEdge::kElement:
     case i::HeapGraphEdge::kHidden:
+    case i::HeapGraphEdge::kWeak:
       return ToApiHandle<Number>(
           isolate->factory()->NewNumberFromInt(edge->index()));
     default: UNREACHABLE();
   }
   return v8::Undefined();
 }
 
 
 const HeapGraphNode* HeapGraphEdge::GetFromNode() const {
   i::Isolate* isolate = i::Isolate::Current();
@@ skipping 483 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   return callback(info);
 }
 
 
 } }  // namespace v8::internal