[PDF] Improve complex xfer mode support.

Xfer mode applies only to the shape of the source drawing, not everything in the clip as in currently implemented.  It's just that the current gm examples draw a shape that fills the visible layer.

R=edisonn@google.com, reed@google.com

Review URL: https://codereview.appspot.com/4631078

git-svn-id: http://skia.googlecode.com/svn/trunk/include@12034 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed