Merge to XFA: Rename IFXJS_Runtime and IFXJS_Context to IJS_.

Merge conflicts in:
  fpdfsdk/src/javascript/Document.cpp
  fpdfsdk/src/javascript/JS_Define.h

New code in:
 fpdfsdk/include/fpdfxfa/fpdfxfa_doc.h
 fpdfsdk/src/fpdfxfa/fpdfxfa_doc.cpp

(cherry picked from commit 213a172779fddbd7e588ee2e2b3906ccc47d6896)
Original Review URL: https://codereview.chromium.org/1386173002 .

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1395713002 .
36 files changed