New Heap Profiler: add API method for finding a graph node by id.

src/api.cc

 // Copyright 2010 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 4854 matching lines @@
       ToInternal(this)->title())));
 }
 
 
 const HeapGraphNode* HeapSnapshot::GetRoot() const {
   IsDeadCheck("v8::HeapSnapshot::GetHead");
   return reinterpret_cast<const HeapGraphNode*>(ToInternal(this)->root());
 }
 
 
+const HeapGraphNode* HeapSnapshot::GetNodeById(uint64_t id) const {
+  IsDeadCheck("v8::HeapSnapshot::GetNodeById");
+  return reinterpret_cast<const HeapGraphNode*>(
+      ToInternal(this)->GetEntryById(id));
+}
+
+
 const HeapSnapshotsDiff* HeapSnapshot::CompareWith(
     const HeapSnapshot* snapshot) const {
   IsDeadCheck("v8::HeapSnapshot::CompareWith");
   return reinterpret_cast<const HeapSnapshotsDiff*>(
       ToInternal(this)->CompareWith(ToInternal(snapshot)));
 }
 
 
 void HeapSnapshot::Serialize(OutputStream* stream,
                              HeapSnapshot::SerializationFormat format) const {
@@ skipping 129 matching lines @@
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* thread_local =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   thread_local->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
 } }  // namespace v8::internal