Revert "Revert "switch GatherPixelRefs to use SkBaseDevice instead of SkBitmapDevice""

This reverts commit ff0152ec5e2a0faf38ae1a317c5d77df08139104.

BUG=

Review URL: https://codereview.chromium.org/68203018

git-svn-id: http://skia.googlecode.com/svn/trunk/include@12271 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed