StringPiece is more permissive as an input parameter than std::string. However, a function accepting StringPiece can require an extra copy if it forwards a StringPiece to a function that requires a std::string. Therefore, accepting StringPiece at low levels in the stack enables higher levels to also accept StringPiece without losing efficiency.

This tracks converting the functions provided by net/base/escape.h to accept string inputs as StringPiece or StringPiece16.