Remove mojo::String.

mojo/common/common_type_converters.cc

Index: mojo/common/common_type_converters.cc
diff --git a/mojo/common/common_type_converters.cc b/mojo/common/common_type_converters.cc
index 92ae3e2682034aaaaa1e396ec46f9e2ddda3c8bb..8c80d269f4c94168f6fa380bedcb32c77cc8bdb3 100644
--- a/mojo/common/common_type_converters.cc
+++ b/mojo/common/common_type_converters.cc
@@ -8,37 +8,8 @@
 
 #include <string>
 
-#include "base/strings/utf_string_conversions.h"
-
 namespace mojo {
 
-// static
-String TypeConverter<String, base::StringPiece>::Convert(
-    const base::StringPiece& input) {
-  if (input.empty()) {
-    char c = 0;
-    return String(&c, 0);
-  }
-  return String(input.data(), input.size());
-}
-// static
-base::StringPiece TypeConverter<base::StringPiece, String>::Convert(
-    const String& input) {
-  return input.get();
-}
-
-// static
-String TypeConverter<String, base::string16>::Convert(
-    const base::string16& input) {
-  return TypeConverter<String, base::StringPiece>::Convert(
-      base::UTF16ToUTF8(input));
-}
-// static
-base::string16 TypeConverter<base::string16, String>::Convert(
-    const String& input) {
-  return base::UTF8ToUTF16(input.To<base::StringPiece>());
-}
-
 std::string TypeConverter<std::string, Array<uint8_t>>::Convert(
     const Array<uint8_t>& input) {
   if (input.is_null() || input.empty())