Deprecate file_util::AppendToPath() on non-Windows.

base/file_util_unittest.cc

Index: base/file_util_unittest.cc
diff --git a/base/file_util_unittest.cc b/base/file_util_unittest.cc
index ae6560dc7b45203236baadeda032a7ec5e6a6331..fa927372facb97a9a945f8f0ae69dcdb07d84aba 100644
--- a/base/file_util_unittest.cc
+++ b/base/file_util_unittest.cc
@@ -145,6 +145,8 @@ const struct append_case {
 #endif
 };
 
+#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];
@@ -157,6 +159,8 @@ TEST_F(FileUtilTest, AppendToPath) {
   file_util::AppendToPath(NULL, L"path");  // asserts in debug mode
 #endif
 }
+#endif  // defined(OS_WIN)
+
 
 static const struct InsertBeforeExtensionCase {
   const FilePath::CharType* path;