In TiledPictureRenderer and CopyTilesRenderer, do a postTranslate so
the translate is not affected by the scale factor.
Likewise, use clipRegion for tiled renderer so it will be
unaffected by the scale factor.
Respect the viewport for record, playbackCreation, and pipe renderers.
Review URL: https://codereview.appspot.com/6947072
git-svn-id: http://skia.googlecode.com/svn/trunk@6853 2bbb7eff-a529-9590-31e7-b0007b416f81