Standardize usage of virtual/override/final in mojo/

mojo/public/c/system/tests/core_perftest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This tests the performance of the C API.
 
 #include "mojo/public/c/system/core.h"
 
 #include <assert.h>
 #include <stddef.h>
@@ skipping 11 matching lines @@
 #include "mojo/public/cpp/utility/thread.h"
 #endif  // !defined(WIN32)
 
 namespace {
 
 #if !defined(WIN32)
 class MessagePipeWriterThread : public mojo::Thread {
  public:
   MessagePipeWriterThread(MojoHandle handle, uint32_t num_bytes)
       : handle_(handle), num_bytes_(num_bytes), num_writes_(0) {}
-  virtual ~MessagePipeWriterThread() {}
+  ~MessagePipeWriterThread() override {}
 
-  virtual void Run() override {
+  void Run() override {
     char buffer[10000];
     assert(num_bytes_ <= sizeof(buffer));
 
     // TODO(vtl): Should I throttle somehow?
     for (;;) {
       MojoResult result = MojoWriteMessage(
           handle_, buffer, num_bytes_, NULL, 0, MOJO_WRITE_MESSAGE_FLAG_NONE);
       if (result == MOJO_RESULT_OK) {
         num_writes_++;
         continue;
@@ skipping 15 matching lines @@
   const uint32_t num_bytes_;
   int64_t num_writes_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MessagePipeWriterThread);
 };
 
 class MessagePipeReaderThread : public mojo::Thread {
  public:
   explicit MessagePipeReaderThread(MojoHandle handle)
       : handle_(handle), num_reads_(0) {}
-  virtual ~MessagePipeReaderThread() {}
+  ~MessagePipeReaderThread() override {}
 
-  virtual void Run() override {
+  void Run() override {
     char buffer[10000];
 
     for (;;) {
       uint32_t num_bytes = static_cast<uint32_t>(sizeof(buffer));
       MojoResult result = MojoReadMessage(
           handle_, buffer, &num_bytes, NULL, NULL, MOJO_READ_MESSAGE_FLAG_NONE);
       if (result == MOJO_RESULT_OK) {
         num_reads_++;
         continue;
       }
@@ skipping 240 matching lines @@
   DoMessagePipeThreadedTest(1u, 1u, 10000u);
 
   DoMessagePipeThreadedTest(3u, 3u, 10u);
   // 100 was done above.
   DoMessagePipeThreadedTest(3u, 3u, 1000u);
   DoMessagePipeThreadedTest(3u, 3u, 10000u);
 }
 #endif  // !defined(WIN32)
 
 }  // namespace