Scrollable should use scrollTo() when starting an animation

Scrollable should use scrollTo() instead of setting _scrollOffset directly, when starting an animation.

I'd missed this case when adding Scrollable.scrollTo()
https://codereview.chromium.org/1074033002

R=ianh@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/1eb155ed8c7da36014a609cdd34b5b78d8822cee

[hansmuller1, 2015-04-13 23:56:28]

hansmuller@google.com changed reviewers:
+ ianh@google.com

[hansmuller1, 2015-04-13 23:57:30]

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

[hansmuller1, 2015-04-13 23:57:31]

PTAL

[Hixie, 2015-04-14 16:52:30]

LGTM with the minor style change

https://codereview.chromium.org/1082163002/diff/1/sky/framework/components/sc...
File sky/framework/components/scrollable.dart (right):

https://codereview.chromium.org/1082163002/diff/1/sky/framework/components/sc...
sky/framework/components/scrollable.dart:72: _simulation.onTick.listen((_)
{scrollTo(particle.position);});
Keep it on three lines or use the => form.

[hansmuller, 2015-04-14 17:01:51]

Committed patchset #1 (id:1) manually as
1eb155ed8c7da36014a609cdd34b5b78d8822cee (presubmit successful).