Merge to XFA: Remove unneeded checks in CPDF_DocPageData::GetFontFileStreamAcc().

The input cannot be null. Same for CPDF_Document::LoadFontFile().

Also set the contract for CPDF_Document::LoadFont() and adjust callers
accordingly.

Also remove unused CPDF_Document::FindFont().

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1184673002.

(cherry picked from commit 1972b16849fedfda675eacd5c8594b54dbd1264d)

Review URL: https://codereview.chromium.org/1181393002.
4 files changed