Add a gyp flag to enable dcheck by default in release without

base/file_util_unittest.cc

 // Copyright (c) 2011 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 205 matching lines @@
 #if defined(OS_WIN)
 // This function is deprecated, but still used on Windows.
 TEST_F(FileUtilTest, AppendToPath) {
   for (unsigned int i = 0; i < arraysize(append_cases); ++i) {
     const append_case& value = append_cases[i];
     std::wstring result = value.path;
     file_util::AppendToPath(&result, value.ending);
     EXPECT_EQ(value.result, result);
   }
 
-#ifdef NDEBUG
+#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
   file_util::AppendToPath(NULL, L"path");  // asserts in debug mode
 #endif
 }
 #endif  // defined(OS_WIN)
 
 static const struct filename_case {
   const wchar_t* path;
   const wchar_t* filename;
 } filename_cases[] = {
 #if defined(OS_WIN)
@@ skipping 1570 matching lines @@
   EXPECT_TRUE(file_util::IsDirectoryEmpty(empty_dir));
 
   FilePath foo(empty_dir.Append(FILE_PATH_LITERAL("foo.txt")));
   std::string bar("baz");
   ASSERT_TRUE(file_util::WriteFile(foo, bar.c_str(), bar.length()));
 
   EXPECT_FALSE(file_util::IsDirectoryEmpty(empty_dir));
 }
 
 }  // namespace