Revert "remove SK_SUPPORT_LEGACY_PDF_PIXELSERIALIZER dead code"

This reverts commit 7f846f273ceaa5a3a8880e9af260f94bd1e614b6.

Reason for revert: missed callsite in google3

Original change's description:
> remove SK_SUPPORT_LEGACY_PDF_PIXELSERIALIZER dead code
> 
> Bug: skia:
> Change-Id: Ia88f3e2fdf6d5c6e5128eaefda0d68c7042ae7a2
> Reviewed-on: https://skia-review.googlesource.com/85500
> Commit-Queue: Mike Reed <reed@google.com>
> Reviewed-by: Hal Canary <halcanary@google.com>

TBR=halcanary@google.com,reed@google.com

Change-Id: I232dc24831bd8d52e9cbbc7ee58177af0617574a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/85600
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
10 files changed