ShrinkWrap the Stocks menu

ShrinkWrap the Stocks menu

The popup menu in the stocks app is supposed to size its width to the max
intrinsic width of the menu. This CL teaches it how to do that.

It's a shame that we need to ceilToDouble the output of RenderParagraph. If we
don't do that, we run into floating point layout trouble and the menu triggers
a line break. The correct fix is to do layout in fixed point.

R=ianh@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/d1bf4e9e9a8f38031653a4042873b677e7a3cddb

[Hixie, 2015-06-08 23:00:36]

lgtm

LGTM with comments

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
File sky/sdk/lib/framework/rendering/box.dart (right):

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
sky/sdk/lib/framework/rendering/box.dart:333: RenderShrinkWrapWidth({ RenderBox
child }) : super(child);
if you're requiring child to be non-null, assert it in the constructor and in
the setter. otherwise, handle null children everywhere here.

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
sky/sdk/lib/framework/rendering/box.dart:338: return new
BoxConstraints(minWidth: width,
don't we have a BoxConstraints constructor for this case?

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
File sky/sdk/lib/framework/rendering/paragraph.dart (right):

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
sky/sdk/lib/framework/rendering/paragraph.dart:63: _layout(constraints);
Isn't this destructive?

What if someone calls getMinIntrinsicWidth() with various constraints during
paint, e.g. to draw lines at the various dimensions, then draws the text on top
of that?

[abarth-chromium, 2015-06-08 23:20:16]

Committed patchset #2 (id:20001) manually as
d1bf4e9e9a8f38031653a4042873b677e7a3cddb (presubmit successful).

[abarth-chromium, 2015-06-09 00:40:30]

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
File sky/sdk/lib/framework/rendering/box.dart (right):

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
sky/sdk/lib/framework/rendering/box.dart:333: RenderShrinkWrapWidth({ RenderBox
child }) : super(child);
On 2015/06/08 at 23:00:36, Hixie wrote:
> if you're requiring child to be non-null, assert it in the constructor and in
the setter. otherwise, handle null children everywhere here.

Fixed to handle null.

https://codereview.chromium.org/1168113005/diff/1/sky/sdk/lib/framework/rende...
sky/sdk/lib/framework/rendering/box.dart:338: return new
BoxConstraints(minWidth: width,
On 2015/06/08 at 23:00:35, Hixie wrote:
> don't we have a BoxConstraints constructor for this case?

Added applyWidth