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

ipc/ipc_perftest_support.cc

Index: ipc/ipc_perftest_support.cc
diff --git a/ipc/ipc_perftest_support.cc b/ipc/ipc_perftest_support.cc
index ab06ed61b94b5259d81d7f0530ad9868f2cd84f6..e60de91ec60782d1584104a6ecf718e21c18409e 100644
--- a/ipc/ipc_perftest_support.cc
+++ b/ipc/ipc_perftest_support.cc
@@ -81,7 +81,7 @@
     VLOG(1) << "Client listener up";
   }
 
-  ~ChannelReflectorListener() override {
+  virtual ~ChannelReflectorListener() {
     VLOG(1) << "Client listener down";
     latency_tracker_.ShowResults();
   }
@@ -91,7 +91,7 @@
     channel_ = channel;
   }
 
-  bool OnMessageReceived(const Message& message) override {
+  virtual bool OnMessageReceived(const Message& message) override {
     CHECK(channel_);
 
     PickleIterator iter(message);
@@ -142,7 +142,9 @@
     VLOG(1) << "Server listener up";
   }
 
-  ~PerformanceChannelListener() override { VLOG(1) << "Server listener down"; }
+  virtual ~PerformanceChannelListener() {
+    VLOG(1) << "Server listener down";
+  }
 
   void Init(Sender* sender) {
     DCHECK(!sender_);
@@ -158,7 +160,7 @@
     payload_ = std::string(msg_size_, 'a');
   }
 
-  bool OnMessageReceived(const Message& message) override {
+  virtual bool OnMessageReceived(const Message& message) override {
     CHECK(sender_);
 
     PickleIterator iter(message);