Fix typo in doxygen comments for texture.h.
Fix typo in doxygen comments for texture.h.

Correct the return type listed in comments for Texture's original_size function.
PiperOrigin-RevId: 143038069
Change-Id: I1058d4f38f96ca0454b187d855bc9bd04261127b

google/fplbase,google/fplbase,google/fplbase,google/fplbase