Merge to XFA: Kill IFX_FontMapper

(cherry picked from commit 01fa1efb228acdcf5250804c670107133668e4b2)
Orignal Review URL: https://codereview.chromium.org/1259123005 .

conflicts:
  core/include/fxge/fx_font.h
  core/src/fxge/ge/fx_ge_fontmap.cpp

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1262723006 .
5 files changed