Revert "Revert "Revert "Cleanup some numeric code."""

core/src/fxcrt/fx_extension_unittest.cpp

-// Copyright 2015 PDFium 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 "testing/gtest/include/gtest/gtest.h"
-
-#include "../../include/fxcrt/fx_ext.h"
-
-TEST(fxcrt, FXSYS_toHexDigit) {
-  EXPECT_EQ(10, FXSYS_toHexDigit('a'));
-  EXPECT_EQ(10, FXSYS_toHexDigit('A'));
-  EXPECT_EQ(7, FXSYS_toHexDigit('7'));
-  EXPECT_EQ(0, FXSYS_toHexDigit('i'));
-}
-
-TEST(fxcrt, FXSYS_toDecimalDigit) {
-  EXPECT_EQ(7, FXSYS_toDecimalDigit('7'));
-  EXPECT_EQ(0, FXSYS_toDecimalDigit('a'));
-}