Warn on missing OVERRIDE/virtual everywhere, not just in header files.

cc/trees/layer_tree_host_unittest_animation.cc

 // Copyright 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 "cc/trees/layer_tree_host.h"
 
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/timing_function.h"
 #include "cc/layers/layer.h"
@@ skipping 690 matching lines @@
 
   virtual void DispatchAddInstantAnimation(Layer* layer_to_receive_animation)
       OVERRIDE {
     LayerTreeHostAnimationTest::DispatchAddInstantAnimation(
         layer_to_receive_animation);
     added_animations_++;
   }
 
   virtual bool PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
                                      LayerTreeHostImpl::FrameData* frame_data,
-                                     bool result) {
+                                     bool result) OVERRIDE {
     if (added_animations_ < 2)
       return result;
     // Act like there is checkerboard when the second animation wants to draw.
     return false;
   }
 
   virtual void DidCommitAndDrawFrame() OVERRIDE {
     switch (layer_tree_host()->commit_number()) {
       case 1:
         // The animation is longer than 1 vsync.
@@ skipping 99 matching lines @@
   FakeContentLayerClient client_;
   scoped_refptr<FakeContentLayer> root_layer_;
   int started_times_;
   int num_commit_complete_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostAnimationTestPinchZoomScrollbars);
 
 }  // namespace
 }  // namespace cc