Remove redundant setState() calls around scroll behaviour updates.

Remove redundant setState() calls around scroll behaviour updates.
We don't need to rebuild when those change; we only got the change because we rebuilt in the first place.

R=jackson@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/c26915502dd50336603c00da37a38e6778db3079

[jackson, 2015-07-13 19:00:34]

jackson@google.com changed reviewers:
+ jackson@google.com

[jackson, 2015-07-13 19:00:34]

lgtm

[hansmuller, 2015-07-13 19:03:52]

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

[hansmuller, 2015-07-13 19:03:53]

https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
File sky/sdk/lib/widgets/variable_height_scrollable.dart (right):

https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
sky/sdk/lib/widgets/variable_height_scrollable.dart:33:
scrollBehavior.containerSize = newSize.height;
If the viewport's size changes, don't you want to layout/paint?

[Hixie, 2015-07-13 19:05:42]

On 2015/07/13 at 19:03:53, hansmuller wrote:
>
https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
> File sky/sdk/lib/widgets/variable_height_scrollable.dart (right):
> 
>
https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
> sky/sdk/lib/widgets/variable_height_scrollable.dart:33:
scrollBehavior.containerSize = newSize.height;
> If the viewport's size changes, don't you want to layout/paint?

If the viewport's size changes, you've already laid out / painted. Otherwise you
wouldn't know it had changed.

[Hixie, 2015-07-13 19:05:59]

Committed patchset #1 (id:1) manually as
c26915502dd50336603c00da37a38e6778db3079 (presubmit successful).

[hansmuller, 2015-07-13 19:07:47]

On 2015/07/13 19:05:42, Hixie wrote:
> On 2015/07/13 at 19:03:53, hansmuller wrote:
> >
>
https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
> > File sky/sdk/lib/widgets/variable_height_scrollable.dart (right):
> > 
> >
>
https://codereview.chromium.org/1234863004/diff/1/sky/sdk/lib/widgets/variabl...
> > sky/sdk/lib/widgets/variable_height_scrollable.dart:33:
> scrollBehavior.containerSize = newSize.height;
> > If the viewport's size changes, don't you want to layout/paint?
> 
> If the viewport's size changes, you've already laid out / painted. Otherwise
you
> wouldn't know it had changed.

So when the phone shifts from portrait to landscape mode, we relayout, paint,
and then notify size observers?