Merge six commits from master-skia to master

Include external/skia/include/private
use SrcConstraint for drawBitmapRect
clean up to allow removal of flags for SCALAR_DIV and IMAGEINFO_FIELDS
don't call DEPRECATED getDevice()
update to newer API for drawBitmapRect
asABitmap is deprecated, used isABitmap

Change-Id: I519f54f97321a7a365ea81a3b78cb03b9bdca021
previous-Change-Id: I12208855a95948897077b1c1549eb35416cc801e
previous-Change-Id: I5044f0f61315fe48c60d7af5e261a7d0ed574f56
previous-Change-Id: Ic34a3ba77b3f9e091fa7aaba75018a307abacdab
previous-Change-Id: I79f8dd779920565d1204f7fe67b3286b1bbf4e9b
previous-Change-Id: Ic04d1f8274f6a862ea00f8d241363cf31f5ec1ec
previous-Change-Id: I9e4ae257a1976c74302b6a73f17405174ae58cec