Revert "Move the rest of src headers used by include to include/private."

This reverts commit d12e6ffa5cc1c1af47bf73c7c127d8d7f7443058.

Our Chrome roll canaries are failing with the dreaded
Ninja-says-there's-more-work-to-do message.  I will break this up
smaller (if possible) and try again tomorrow.

BUG=skia:4126

Review URL: https://codereview.chromium.org/1258293004 .
8 files changed