Remove UTF string conversion functions from the global namespace.

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 f1b9f7242723a139bbe7cd3864b6120eef5b79ff..8787254d28f0c87bfe0c5041580a3e288dca2d73 100644
--- a/third_party/zlib/google/zip_reader.cc
+++ b/third_party/zlib/google/zip_reader.cc
@@ -39,8 +39,8 @@ 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 (!base::UTF8ToUTF16(file_name_in_zip.data(), file_name_in_zip.size(),
+                         &file_name_utf16)) {
     is_unsafe_ = true;
   }