message: Replace ConverterMock in rewriter_test.cc by MockConverter.
diff: namespace mozc {
  namespace {
  -using dictionary::DictionaryInterface;
  -using dictionary::PosGroup;
  +using ::mozc::dictionary::DictionaryInterface;
  +using ::mozc::dictionary::PosGroup;
  size_t CommandCandidatesSize(const Segment &segment) {
  size_t result = 0;
  @@ -68,18 +68,16 @@ class RewriterTest : public ::testing::Test {
  protected:
  void SetUp() override {
  SystemUtil::SetUserProfileDirectory(absl::GetFlag(FLAGS_test_tmpdir));
  - converter_mock_ = std::make_unique<ConverterMock>();
  const testing::MockDataManager data_manager;
  pos_group_ = std::make_unique<PosGroup>(data_manager.GetPosGroupData());
  const DictionaryInterface *kNullDictionary = nullptr;
  - rewriter_ =
  - std::make_unique<RewriterImpl>(converter_mock_.get(), &data_manager,
  - pos_group_.get(), kNullDictionary);
  + rewriter_ = std::make_unique<RewriterImpl>(
  + &mock_converter_, &data_manager, pos_group_.get(), kNullDictionary);
  }
  const RewriterInterface *GetRewriter() const { return rewriter_.get(); }
  - std::unique_ptr<ConverterMock> converter_mock_;
  + MockConverter mock_converter_;
  std::unique_ptr<const PosGroup> pos_group_;
  std::unique_ptr<RewriterImpl> rewriter_;
  };
  