Add virtual and OVERRIDE to base/ implementation files

base/threading/thread_unittest.cc

Index: base/threading/thread_unittest.cc
diff --git a/base/threading/thread_unittest.cc b/base/threading/thread_unittest.cc
index 87df2524b28b060806005c46b2e82906a49d62ff..99ef696e4408c3a98e6bce1be56af28693b1b1f0 100644
--- a/base/threading/thread_unittest.cc
+++ b/base/threading/thread_unittest.cc
@@ -35,7 +35,7 @@ class SleepInsideInitThread : public Thread {
     Stop();
   }
 
-  virtual void Init() {
+  virtual void Init() OVERRIDE {
     base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(500));
     init_called_ = true;
   }
@@ -73,11 +73,11 @@ class CaptureToEventList : public Thread {
     Stop();
   }
 
-  virtual void Init() {
+  virtual void Init() OVERRIDE {
     event_list_->push_back(THREAD_EVENT_INIT);
   }
 
-  virtual void CleanUp() {
+  virtual void CleanUp() OVERRIDE {
     event_list_->push_back(THREAD_EVENT_CLEANUP);
   }
 
@@ -95,7 +95,7 @@ class CapturingDestructionObserver : public MessageLoop::DestructionObserver {
   }
 
   // DestructionObserver implementation:
-  virtual void WillDestroyCurrentMessageLoop() {
+  virtual void WillDestroyCurrentMessageLoop() OVERRIDE {
     event_list_->push_back(THREAD_EVENT_MESSAGE_LOOP_DESTROYED);
     event_list_ = NULL;
   }