Detailed heap snapshot usability improvement.

include/v8-profiler.h

 // 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 458 matching lines @@
   /** Returns whether two instances are equivalent. */
   virtual bool IsEquivalent(RetainedObjectInfo* other) = 0;
 
   /**
    * Returns hash value for the instance. Equivalent instances
    * must have the same hash value.
    */
   virtual intptr_t GetHash() = 0;
 
   /**
-   * Returns human-readable label. It must be a NUL-terminated UTF-8
+   * Returns human-readable label. It must be a null-terminated UTF-8
    * encoded string. V8 copies its contents during a call to GetLabel.
    */
   virtual const char* GetLabel() = 0;
 
   /**
+   * Returns human-readable group label. It must be a null-terminated UTF-8
+   * encoded string. V8 copies its contents during a call to GetGroupLabel.
+   * Heap snapshot generator will collect all the group names, create
+   * top level entries with these names and attach the objects to the
+   * corresponding top level group objects. There is a default
+   * implementation which is required because embedders don't have their
+   * own implementation yet.
+   */
+  virtual const char* GetGroupLabel() { return GetLabel(); }
+
+  /**
    * Returns element count in case if a global handle retains
    * a subgraph by holding one of its nodes.
    */
   virtual intptr_t GetElementCount() { return -1; }
 
   /** Returns embedder's object size in bytes. */
   virtual intptr_t GetSizeInBytes() { return -1; }
 
  protected:
   RetainedObjectInfo() {}
   virtual ~RetainedObjectInfo() {}
 
  private:
   RetainedObjectInfo(const RetainedObjectInfo&);
   RetainedObjectInfo& operator=(const RetainedObjectInfo&);
 };
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 
 
 #endif  // V8_V8_PROFILER_H_