Add virtual and OVERRIDE to base/ implementation files

base/synchronization/waitable_event_unittest.cc

 // Copyright (c) 2011 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.
 
+#include "base/synchronization/waitable_event.h"
+
+#include "base/compiler_specific.h"
 #include "base/time.h"
-#include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 TEST(WaitableEventTest, ManualBasics) {
   WaitableEvent event(true, false);
 
   EXPECT_FALSE(event.IsSignaled());
 
@@ skipping 52 matching lines @@
     delete ev[i];
 }
 
 class WaitableEventSignaler : public PlatformThread::Delegate {
  public:
   WaitableEventSignaler(double seconds, WaitableEvent* ev)
       : seconds_(seconds),
         ev_(ev) {
   }
 
-  void ThreadMain() {
+  virtual void ThreadMain() OVERRIDE {
     PlatformThread::Sleep(TimeDelta::FromSeconds(static_cast<int>(seconds_)));
     ev_->Signal();
   }
 
  private:
   const double seconds_;
   WaitableEvent *const ev_;
 };
 
 TEST(WaitableEventTest, WaitMany) {
   WaitableEvent* ev[5];
   for (unsigned i = 0; i < 5; ++i)
     ev[i] = new WaitableEvent(false, false);
 
   WaitableEventSignaler signaler(0.1, ev[2]);
   PlatformThreadHandle thread;
   PlatformThread::Create(0, &signaler, &thread);
 
   EXPECT_EQ(WaitableEvent::WaitMany(ev, 5), 2u);
 
   PlatformThread::Join(thread);
 
   for (unsigned i = 0; i < 5; ++i)
     delete ev[i];
 }
 
 }  // namespace base