Use StringPiece for UTF string conversions.

third_party/zlib/google/zip_reader.cc

Index: third_party/zlib/google/zip_reader.cc
diff --git a/third_party/zlib/google/zip_reader.cc b/third_party/zlib/google/zip_reader.cc
index 6ea8025094151de4bb83a7947057b0b6dc616387..43379a6e20eeed61a2ee0eda9a92a04d48476dd9 100644
--- a/third_party/zlib/google/zip_reader.cc
+++ b/third_party/zlib/google/zip_reader.cc
@@ -40,8 +40,7 @@ ZipReader::EntryInfo::EntryInfo(const std::string& file_name_in_zip,
 
   // We also consider that the file name is unsafe, if it's invalid UTF-8.
   base::string16 file_name_utf16;
-  if (!UTF8ToUTF16(file_name_in_zip.data(), file_name_in_zip.size(),
-                   &file_name_utf16)) {
+  if (!UTF8ToUTF16(file_name_in_zip, &file_name_utf16)) {
     is_unsafe_ = true;
   }