[runtime] Introduce dedicated JSBoundFunction to represent bound functions.

test/cctest/test-heap-profiler.cc

 // Copyright 2011 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 233 matching lines @@
   CHECK(ValidateSnapshot(snapshot));
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   const v8::HeapGraphNode* f =
       GetProperty(global, v8::HeapGraphEdge::kProperty, "boundFunction");
   CHECK(f);
   CHECK(v8_str("native_bind")->Equals(env.local(), f->GetName()).FromJust());
   const v8::HeapGraphNode* bindings =
       GetProperty(f, v8::HeapGraphEdge::kInternal, "bindings");
   CHECK(bindings);
   CHECK_EQ(v8::HeapGraphNode::kArray, bindings->GetType());
-  CHECK_EQ(3, bindings->GetChildrenCount());
+  CHECK_EQ(1, bindings->GetChildrenCount());
 
   const v8::HeapGraphNode* bound_this = GetProperty(
       f, v8::HeapGraphEdge::kShortcut, "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");
   CHECK(bound_function);
   CHECK_EQ(v8::HeapGraphNode::kClosure, bound_function->GetType());
@@ skipping 2580 matching lines @@
   map.AddRange(ToAddress(0x180), 0x80, 6U);
   map.AddRange(ToAddress(0x180), 0x80, 7U);
   CHECK_EQ(7u, map.GetTraceNodeId(ToAddress(0x180)));
   CHECK_EQ(5u, map.GetTraceNodeId(ToAddress(0x200)));
   CHECK_EQ(3u, map.size());
 
   map.Clear();
   CHECK_EQ(0u, map.size());
   CHECK_EQ(0u, map.GetTraceNodeId(ToAddress(0x400)));
 }