Add support for per-isolate private symbols

src/isolate.h

 // 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 1108 matching lines @@
   Object* FindCodeObject(Address a);
 
   int NextOptimizationId() {
     int id = next_optimization_id_++;
     if (!Smi::IsValid(next_optimization_id_)) {
       next_optimization_id_ = 0;
     }
     return id;
   }
 
+  // Get (and lazily initialize) the registry for per-isolate symbols.
+  Handle<JSObject> GetSymbolRegistry();
+
  private:
   Isolate();
 
   friend struct GlobalState;
   friend struct InitializeGlobalState;
 
   enum State {
     UNINITIALIZED,    // Some components may not have been allocated.
     INITIALIZED       // All components are fully initialized.
   };
@@ skipping 411 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_