Mark function used as template parameter extern.

VC++19.10.2517 does not support the C++11 change to allow the address of
internal linkage objects to be used as non-type template arguments.

BUG=skia:6351

Change-Id: I7e1f628db794f950dfba7d043cf6d2fbf0a8c453
Reviewed-on: https://skia-review.googlesource.com/9496
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed