Revert of Standardize usage of virtual/override/final in ipc/

ipc/ipc_fuzzing_tests.cc

Index: ipc/ipc_fuzzing_tests.cc
diff --git a/ipc/ipc_fuzzing_tests.cc b/ipc/ipc_fuzzing_tests.cc
index f9475a1adb0015fdf7f80b0dc5e7dae7487fec86..a85491c72f220204357ffc99263b0c0bf4076f48 100644
--- a/ipc/ipc_fuzzing_tests.cc
+++ b/ipc/ipc_fuzzing_tests.cc
@@ -135,7 +135,7 @@
  public:
   FuzzerServerListener() : message_count_(2), pending_messages_(0) {
   }
-  bool OnMessageReceived(const IPC::Message& msg) override {
+  virtual bool OnMessageReceived(const IPC::Message& msg) override {
     if (msg.routing_id() == MSG_ROUTING_CONTROL) {
       ++pending_messages_;
       IPC_BEGIN_MESSAGE_MAP(FuzzerServerListener, msg)
@@ -199,7 +199,7 @@
   FuzzerClientListener() : last_msg_(NULL) {
   }
 
-  bool OnMessageReceived(const IPC::Message& msg) override {
+  virtual bool OnMessageReceived(const IPC::Message& msg) override {
     last_msg_ = new IPC::Message(msg);
     base::MessageLoop::current()->Quit();
     return true;