Don't unload debug context after it was requested through public API

src/debug.cc

 // Copyright 2006-2008 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 2115 matching lines @@
                               Handle<Object>::cast(event_data).location(),
                               event_listener_data_.location() };
       Handle<Object> result = Execution::TryCall(fun, Top::global(),
                                                  argc, argv, &caught_exception);
       // Silently ignore exceptions from debug event listeners.
     }
   }
 }
 
 
+Handle<Context> Debugger::GetDebugContext() {
+    never_unload_debugger_ = true;
+    EnterDebugger debugger;
+    return Debug::debug_context();
+}
+
+
 void Debugger::UnloadDebugger() {
   // Make sure that there are no breakpoints left.
   Debug::ClearAllBreakPoints();
 
   // Unload the debugger if feasible.
   if (!never_unload_debugger_) {
     Debug::Unload();
   }
 
   // Clear the flag indicating that the debugger should be unloaded.
@@ skipping 649 matching lines @@
     {
       Locker locker;
       Debugger::CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal