[heap profiler] Use internal type links for bound this and target function.

These are internal fields of the JSBoundFunction class.

Review-Url: https://codereview.chromium.org/2193993002
Cr-Commit-Position: refs/heads/master@{#38222}

src/profiler/heap-snapshot-generator.cc

@@ -1089,9 +1089,11 @@ void V8HeapExplorer::ExtractJSObjectReferences(
     TagObject(js_fun->bound_arguments(), "(bound arguments)");
     SetInternalReference(js_fun, entry, "bindings", js_fun->bound_arguments(),
                          JSBoundFunction::kBoundArgumentsOffset);
-    SetNativeBindReference(js_obj, entry, "bound_this", js_fun->bound_this());
-    SetNativeBindReference(js_obj, entry, "bound_function",
-                           js_fun->bound_target_function());
+    SetInternalReference(js_obj, entry, "bound_this", js_fun->bound_this(),
+                         JSBoundFunction::kBoundThisOffset);
+    SetInternalReference(js_obj, entry, "bound_function",
+                         js_fun->bound_target_function(),
+                         JSBoundFunction::kBoundTargetFunctionOffset);
     FixedArray* bindings = js_fun->bound_arguments();
     for (int i = 0; i < bindings->length(); i++) {
       const char* reference_name = names_->GetFormatted("bound_argument_%d", i);

test/cctest/test-heap-profiler.cc

@@ -256,13 +256,13 @@ TEST(BoundFunctionInSnapshot) {
   CHECK_EQ(v8::HeapGraphNode::kArray, bindings->GetType());
   CHECK_EQ(1, bindings->GetChildrenCount());
 
-  const v8::HeapGraphNode* bound_this = GetProperty(
-      f, v8::HeapGraphEdge::kShortcut, "bound_this");
+  const v8::HeapGraphNode* bound_this =
+      GetProperty(f, v8::HeapGraphEdge::kInternal, "bound_this");
   CHECK(bound_this);
   CHECK_EQ(v8::HeapGraphNode::kObject, bound_this->GetType());
 
-  const v8::HeapGraphNode* bound_function = GetProperty(
-      f, v8::HeapGraphEdge::kShortcut, "bound_function");
+  const v8::HeapGraphNode* bound_function =
+      GetProperty(f, v8::HeapGraphEdge::kInternal, "bound_function");
   CHECK(bound_function);
   CHECK_EQ(v8::HeapGraphNode::kClosure, bound_function->GetType());