Revert "[PDF] Move most of the headers to be private."

This reverts r3457

TBR=epoger@google.com

Review URL: https://codereview.appspot.com/5866051

git-svn-id: http://skia.googlecode.com/svn/trunk@3458 2bbb7eff-a529-9590-31e7-b0007b416f81
14 files changed