clang/win: Fix most -Wunused-function warnings in Chromium code.

base/files/file_util_unittest.cc

 // Copyright (c) 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 "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 226 matching lines @@
 std::wstring ReadTextFile(const FilePath& filename) {
   wchar_t contents[64];
   std::wifstream file;
   file.open(filename.value().c_str());
   EXPECT_TRUE(file.is_open());
   file.getline(contents, arraysize(contents));
   file.close();
   return std::wstring(contents);
 }
 
-#if defined(OS_WIN)
-uint64 FileTimeAsUint64(const FILETIME& ft) {
-  ULARGE_INTEGER u;
-  u.LowPart = ft.dwLowDateTime;
-  u.HighPart = ft.dwHighDateTime;
-  return u.QuadPart;
-}
-#endif
-
 TEST_F(FileUtilTest, FileAndDirectorySize) {
   // Create three files of 20, 30 and 3 chars (utf8). ComputeDirectorySize
   // should return 53 bytes.
   FilePath file_01 = temp_dir_.path().Append(FPL("The file 01.txt"));
   CreateTextFile(file_01, L"12345678901234567890");
   int64 size_f1 = 0;
   ASSERT_TRUE(GetFileSize(file_01, &size_f1));
   EXPECT_EQ(20ll, size_f1);
 
   FilePath subdir_path = temp_dir_.path().Append(FPL("Level2"));
@@ skipping 2261 matching lines @@
   // Trying to close it should crash. This is important for security.
   EXPECT_DEATH(CloseWithScopedFD(fds[1]), "");
 #endif
 }
 
 #endif  // defined(OS_POSIX)
 
 }  // namespace
 
 }  // namespace base