Add V8 debugger agent....

src/d8.cc

 // Copyright 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 555 matching lines @@
         Handle<String> file_name = v8::String::New(str);
         Handle<String> source = ReadFile(str);
         if (source.IsEmpty()) {
           printf("Error reading '%s'\n", str);
           return 1;
         }
         if (!ExecuteString(source, file_name, false, true))
           return 1;
       }
     }
-    if (i::FLAG_debugger)
+
+    // Start the debugger agent if requested.
+    if (i::FLAG_debugger_agent) {
+      v8::Debug::EnableAgent(i::FLAG_debugger_port);
+    }
+
+    // Start the in-process debugger if requested.
+    if (i::FLAG_debugger && !i::FLAG_debugger_agent)
       v8::Debug::SetDebugEventListener(HandleDebugEvent);
   }
+
   if (run_shell)
     RunShell();
   for (int i = 0; i < threads.length(); i++) {
     i::Thread *thread = threads[i];
     thread->Join();
     delete thread;
   }
   OnExit();
   return 0;
 }
 
 
 }  // namespace v8
 
 
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }