Fix a bug when zip files in a directory containing locale characters in path.

BUG=248115
TEST=manual testing on windows

Review URL: https://chromiumcodereview.appspot.com/16632007

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d9551eaa68a55f771798771f05ee8a9e88d73b3b
diff --git a/google/zip.cc b/google/zip.cc
index 881c0ca..9e2de0d 100644
--- a/google/zip.cc
+++ b/google/zip.cc
@@ -52,7 +52,7 @@
 bool AddEntryToZip(zipFile zip_file, const base::FilePath& path,
                    const base::FilePath& root_path) {
   std::string str_path =
-      path.AsUTF8Unsafe().substr(root_path.value().length() + 1);
+      path.AsUTF8Unsafe().substr(root_path.AsUTF8Unsafe().length() + 1);
 #if defined(OS_WIN)
   ReplaceSubstringsAfterOffset(&str_path, 0u, "\\", "/");
 #endif