Make Material actually create material, with opinions about what that
means.
Make FloatingActionButton use this.
Make Scrollable use this.
Make BoxDecoration support drawing a circle instead of a rectangle, so
that floating action button doesn't need a custom painter.
Implement RaisedButton (and remove button.dart, since there's no
"button" in Material Design).
Make InkWell have a "child" argument instead of "children", and not
have it introduce a Flex into the hierarchy.
Update container.dart example. Clean up some imports.
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/1179713004.
This moves input.dart to editing2/, since that way we can define the layering as strictly unidirectional.
It also reorders a bunch of imports to fit the style guide.
I removed the old remnants of the widgets example, and put the fn2 examples into the examples/widgets/ directory, to parallel the framework directory names.
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/1177243002.
