Add d8 functionality for switching between realms (a.k.a. contexts), 2nd try

src/debug.cc

 // 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 594 matching lines @@
 void ScriptCache::Add(Handle<Script> script) {
   GlobalHandles* global_handles = Isolate::Current()->global_handles();
   // Create an entry in the hash map for the script.
   int id = Smi::cast(script->id())->value();
   HashMap::Entry* entry =
       HashMap::Lookup(reinterpret_cast<void*>(id), Hash(id), true);
   if (entry->value != NULL) {
     ASSERT(*script == *reinterpret_cast<Script**>(entry->value));
     return;
   }
-
   // Globalize the script object, make it weak and use the location of the
   // global handle as the value in the hash map.
   Handle<Script> script_ =
       Handle<Script>::cast(
           (global_handles->Create(*script)));
   global_handles->MakeWeak(reinterpret_cast<Object**>(script_.location()),
                            this,
                            NULL,
                            ScriptCache::HandleWeakScript);
   entry->value = script_.location();
@@ skipping 3170 matching lines @@
     {
       Locker locker(reinterpret_cast<v8::Isolate*>(isolate_));
       isolate_->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal