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

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index fbde3e739fb213117dbcb107e3240a7dcc06c85c..4d6077e961d8ed3f7c94b1fdecadb8a856c3ca85 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -49,9 +49,6 @@ bool EndsWithSeparator(const FilePath& path);
 // exists. Returns true if |path| is an existing directory, false otherwise.
 bool EnsureEndsWithSeparator(FilePath* path);
 
-// Appends new_ending to path, adding a separator between the two if necessary.
-void AppendToPath(std::wstring* path, const std::wstring& new_ending);
-
 // Convert provided relative path into an absolute path.  Returns false on
 // error. On POSIX, this function fails if the path does not exist.
 bool AbsolutePath(FilePath* path);