Fix deadlock when terminating debugger session.

src/debug-agent.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 139 matching lines @@
 void DebuggerAgent::OnSessionClosed(DebuggerAgentSession* session) {
   // Don't do anything during termination.
   if (terminate_) {
     return;
   }
 
   // Terminate the session.
   ScopedLock with(session_access_);
   ASSERT(session == session_);
   if (session == session_) {
-    CloseSession();
+    session_->Shutdown();
+    delete session_;
+    session_ = NULL;
   }
 }
 
 
 void DebuggerAgentSession::Run() {
   // Send the hello message.
   bool ok = DebuggerAgentUtil::SendConnectMessage(client_, *agent_->name_);
   if (!ok) return;
 
   while (true) {
@@ skipping 287 matching lines @@
       return total_received;
     }
     total_received += received;
   }
   return total_received;
 }
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT