Port DrawerHeader to fn2 world.

Port DrawerHeader to fn2 world.

This includes making SizedBox default to infinite size, and making
Container default to containing one infinite-sized SizedBox. That way,
you can use an empty Container as a spacer in a flex box.

The rendering doesn't quite work, because of a bug in flex whereby it
doesn't shrink-wrap its contents in the cross-direction, it fills the
parent. Collin is on that.

R=jackson@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/8019c6f09df325f8d389954ff05f549cf01bf178

[eseidel, 2015-06-08 17:55:19]

eseidel@chromium.org changed reviewers:
+ eseidel@chromium.org

[eseidel, 2015-06-08 17:55:21]

lgtm

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/c...
File sky/sdk/lib/framework/components2/drawer_header.dart (right):

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/c...
sky/sdk/lib/framework/components2/drawer_header.dart:26: color: const
sky.Color(0xFFD1D9E1),
sky.

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/c...
sky/sdk/lib/framework/components2/drawer_header.dart:39: desiredSize:
sky.Size.infinite
sky.

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/f...
File sky/sdk/lib/framework/fn2.dart (right):

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/f...
sky/sdk/lib/framework/fn2.dart:411: this.desiredSize: sky.Size.infinite,
sky.

https://codereview.chromium.org/1163633003/diff/80001/sky/sdk/lib/framework/f...
sky/sdk/lib/framework/fn2.dart:973: current = new SizedBox();
What is a sized box with no size?  0x0?

[jackson, 2015-06-08 17:55:53]

jackson@google.com changed reviewers:
+ jackson@google.com
- eseidel@chromium.org

[jackson, 2015-06-08 17:55:54]

lgtm

lgtm

[Hixie, 2015-06-08 18:00:10]

Committed patchset #6 (id:100001) manually as
8019c6f09df325f8d389954ff05f549cf01bf178 (presubmit successful).