Add virtual and OVERRIDE to base/ implementation files

base/message_loop_proxy_impl_unittest.cc

Index: base/message_loop_proxy_impl_unittest.cc
diff --git a/base/message_loop_proxy_impl_unittest.cc b/base/message_loop_proxy_impl_unittest.cc
index 612312a6053acfcdc9b49ad43f4e27cc1233c642..e97d8f17a200dde58031abf110a95236b4b775db 100644
--- a/base/message_loop_proxy_impl_unittest.cc
+++ b/base/message_loop_proxy_impl_unittest.cc
@@ -37,14 +37,14 @@ class MessageLoopProxyImplTest : public testing::Test {
   }
 
  protected:
-  virtual void SetUp() {
+  virtual void SetUp() OVERRIDE {
     io_thread_.reset(new base::Thread("MessageLoopProxyImplTest_IO"));
     file_thread_.reset(new base::Thread("MessageLoopProxyImplTest_File"));
     io_thread_->Start();
     file_thread_->Start();
   }
 
-  virtual void TearDown() {
+  virtual void TearDown() OVERRIDE {
     io_thread_->Stop();
     file_thread_->Stop();
   }