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

cc/resources/tile_manager_unittest.cc

 // Copyright 2013 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/resources/tile.h"
 #include "cc/test/fake_tile_manager.h"
 #include "cc/test/fake_tile_manager_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
 namespace {
 
 class FakePicturePileImpl : public PicturePileImpl {
  public:
   FakePicturePileImpl() : PicturePileImpl(false) {
     gfx::Size size(std::numeric_limits<int>::max(),
                    std::numeric_limits<int>::max());
     Resize(size);
     recorded_region_ = Region(gfx::Rect(size));
   }
 
  protected:
-  ~FakePicturePileImpl() {}
+  virtual ~FakePicturePileImpl() {}
 };
 
 class TilePriorityForEventualBin : public TilePriority {
  public:
     TilePriorityForEventualBin() : TilePriority(
             NON_IDEAL_RESOLUTION,
             1.0,
             315.0) { }
 };
 
@@ skipping 60 matching lines @@
 
     // Check if pending tiles get memory
     for (TileVector::const_iterator it = tiles_on_pending_tree.begin();
          it != tiles_on_pending_tree.end() ; ++it) {
          EXPECT_TRUE((*it)->IsAssignedGpuMemory());
     }
 }
 
 }  // namespace
 }  // namespace cc