More idiomatic use of constraints in performResize.
Trivial fixes to comments.
Make ProxyBox not use BoxParentData since it ignores the field.
Make applyPaintTransform more helpful if you use a different ParentData
subclass than RenderBox expects.
Make debugAssertIsValid actually fulfill its contract in RenderObject as
documented.
Add a childBefore for symmetry (we already had childAfter).
Fix the way we dump the child list when there's no children in a
multichild render object.
More asserts in the rendering test library.
This reverts commit f41b3411da35929b09009e47cb52474389e42874, reversing
changes made to e33d8d96212f3e337a6660f1eb1118bffc945bf5.
This was a bad check-in due to my mangling uploading a new version of the branch from a different machine.
This reverts https://github.com/flutter/flutter/pull/2639 and will be replaced by https://github.com/flutter/flutter/pull/2640
This makes it more consistent with tightFor(), and also makes it
easier to tighten both directions at once when you're not sure you
will always do so (e.g. if you have a height and width that might be
null, and want to tighten whichever ones aren't null).
