[wip] Add LiteralStringPiece which templatizes based on character length

base/strings/string_piece.h

Index: base/strings/string_piece.h
diff --git a/base/strings/string_piece.h b/base/strings/string_piece.h
index eaec14de5da788ebab2137df35015b9998ec892e..dccd109457895aa2c930cfcd8bcc1429e1a02f6f 100644
--- a/base/strings/string_piece.h
+++ b/base/strings/string_piece.h
@@ -367,6 +367,11 @@ const typename BasicStringPiece<STRING_TYPE>::size_type
 BasicStringPiece<STRING_TYPE>::npos =
     typename BasicStringPiece<STRING_TYPE>::size_type(-1);
 
+template <size_t size>
+inline StringPiece LiteralStringPiece(const char (&array)[size]) {
+  return StringPiece(array, size - 1);
+}
+
 // MSVC doesn't like complex extern templates and DLLs.
 #if !defined(COMPILER_MSVC)
 extern template class BASE_EXPORT BasicStringPiece<std::string>;