Remove logging.h from cc files that don't use it.

base/string_util_unittest.cc

 // Copyright (c) 2006-2008 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 <math.h>
 #include <stdarg.h>
 
 #include <limits>
 #include <sstream>
 
 #include "base/basictypes.h"
-#include "base/logging.h"
 #include "base/string_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 }
 
 static const struct trim_case {
   const wchar_t* input;
   const TrimPositions positions;
   const wchar_t* output;
@@ skipping 1577 matching lines @@
   }
 }
 
 TEST(StringUtilTest, HexEncode) {
   std::string hex(HexEncode(NULL, 0));
   EXPECT_EQ(hex.length(), 0U);
   unsigned char bytes[] = {0x01, 0xff, 0x02, 0xfe, 0x03, 0x80, 0x81};
   hex = HexEncode(bytes, sizeof(bytes));
   EXPECT_EQ(hex.compare("01FF02FE038081"), 0);
 }