Add virtual and OVERRIDE to base/ implementation files

base/synchronization/condition_variable_unittest.cc

Index: base/synchronization/condition_variable_unittest.cc
diff --git a/base/synchronization/condition_variable_unittest.cc b/base/synchronization/condition_variable_unittest.cc
index 49716e1e9c0d354dcf03a4911c97aa211c1c599f..4162d4f608d528bd6d50c12d74684f45dd5c1e6d 100644
--- a/base/synchronization/condition_variable_unittest.cc
+++ b/base/synchronization/condition_variable_unittest.cc
@@ -62,10 +62,10 @@ class ConditionVariableTest : public PlatformTest {
 class WorkQueue : public PlatformThread::Delegate {
  public:
   explicit WorkQueue(int thread_count);
-  ~WorkQueue();
+  virtual ~WorkQueue();
 
   // PlatformThread::Delegate interface.
-  void ThreadMain();
+  virtual void ThreadMain() OVERRIDE;
 
   //----------------------------------------------------------------------------
   // Worker threads only call the following methods.