GitLab

The purpose of this code move is to make it re-usable in order to implement
occlusion culling optimizations in SkPicture similar to what we have now
in SkDeferredCanvas.

BUG=https://code.google.com/p/chromium/issues/detail?id=164530
Review URL: https://codereview.appspot.com/7196046

git-svn-id: http://skia.googlecode.com/svn/trunk@7361 2bbb7eff-a529-9590-31e7-b0007b416f81