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

This reverts r3453

TBR=epoger@google.com

Review URL: https://codereview.appspot.com/5869048

git-svn-id: http://skia.googlecode.com/svn/trunk@3454 2bbb7eff-a529-9590-31e7-b0007b416f81
13 files changed