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

src/debug.h

 // 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 647 matching lines @@
                          bool wait_for_connection = false);
 
   // Stop the debugger agent.
   static void StopAgent();
 
   // Blocks until the agent has started listening for connections
   static void WaitForAgent();
 
   static void CallMessageDispatchHandler();
 
+  static Handle<Context> GetDebugContext();
+
   // Unload the debugger if possible. Only called when no debugger is currently
   // active.
   static void UnloadDebugger();
 
   inline static bool EventActive(v8::DebugEvent event) {
     ScopedLock with(debugger_access_);
 
     // Check whether the message handler was been cleared.
     if (debugger_unload_pending_) {
       if (Debug::debugger_entry() == NULL) {
@@ skipping 224 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 #endif  // V8_DEBUG_H_