Standardize usage of virtual/override/final specifiers in sync/.

sync/internal_api/public/util/weak_handle_unittest.cc

 // Copyright (c) 2012 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 "sync/internal_api/public/util/weak_handle.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/location.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 29 matching lines @@
   MOCK_METHOD1(TestWithSelf, void(const WeakHandle<Base>&));
 
  private:
   base::WeakPtrFactory<Base> weak_ptr_factory_;
 };
 
 class Derived : public Base, public base::SupportsWeakPtr<Derived> {};
 
 class WeakHandleTest : public ::testing::Test {
  protected:
-  virtual void TearDown() {
+  void TearDown() override {
     // Process any last-minute posted tasks.
     PumpLoop();
   }
 
   void PumpLoop() {
     message_loop_.RunUntilIdle();
   }
 
   static void CallTestFromOtherThread(tracked_objects::Location from_here,
                                       const WeakHandle<Base>& h) {
@@ skipping 256 matching lines @@
   EXPECT_FALSE(base_weak_handle.IsInitialized());
 }
 
 TEST_F(WeakHandleTest, TypeConversionConstructorUninitializedAssignment) {
   WeakHandle<Base> base_weak_handle;
   base_weak_handle = WeakHandle<Derived>();
   EXPECT_FALSE(base_weak_handle.IsInitialized());
 }
 
 }  // namespace syncer