Fix implicit includes through string_piece.h The code was relying on string_piece.h to provide the (D)CHECK macros and std::vector (via logging.h). Include the appropriate headers instead. This is motivated by a Chromium change which will make string_piece.h no longer include logging.h. gfe-relnote: n/a (include fix only) PiperOrigin-RevId: 306832924 Change-Id: I7618f6e80ad696a46ecbf36a1f11c6b04c9bb6a5