Merge to XFA: Convert CPDF_FontFileMap to std::map.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1144333008.

(cherry picked from commit f726c92cb2cf5739fd5b21e825e5bf510040c62f)

Review URL: https://codereview.chromium.org/1180653004.
3 files changed