Add SkPDFDeviceFlatenner which extends SkPDFDevice to add support to flatten the path and the text when we have perspective.
prepare to deprecate SkPDFDevice constructor, and route gm and render_pdfs to use SkDocument::Create pdf interface instead. - controlled by a flag
add comments where we are supposed to flatten other features (paint, shaders, ... )

R=reed@google.com, bungeman@google.com, scroggo@google.com, vandebo@chromium.org, bsalomon@google.com

Author: edisonn@google.com

Review URL: https://codereview.chromium.org/24811002

git-svn-id: http://skia.googlecode.com/svn/trunk@11751 2bbb7eff-a529-9590-31e7-b0007b416f81
14 files changed