Make the TaskDescription background color match the ToolBar on Android

Make the TaskDescription background color match the ToolBar on Android

This isn't quite perfect since we seem to do a second layout as the
activity switcher is brought up which is shifting down our
toolbar and making it bleed slightly below the Activity Switcher's
Task description bar.  But at least we're the right color now.

R=abarth@chromium.org, abarth@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/c4603759013c0896fe8b0e5345f0017a76fb8a77

[abarth-chromium, 2015-07-07 19:57:45]

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

[abarth-chromium, 2015-07-07 19:57:46]

LGTM

https://codereview.chromium.org/1209423008/diff/1/sky/sdk/lib/widgets/task_de...
File sky/sdk/lib/widgets/task_description.dart (right):

https://codereview.chromium.org/1209423008/diff/1/sky/sdk/lib/widgets/task_de...
sky/sdk/lib/widgets/task_description.dart:23: void updateTaskDescription(String
label, Color color) {
Can we put this code in sky/sdk/lib/mojo/activity.dart ?  We can store
_cachedPrimaryColor and _cachedLabel as statics in that library.

[eseidel, 2015-07-07 20:56:10]

Committed patchset #2 (id:20001) manually as
c4603759013c0896fe8b0e5345f0017a76fb8a77 (presubmit successful).

[Hixie, 2015-07-07 23:13:02]

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

[Hixie, 2015-07-07 23:13:03]

https://codereview.chromium.org/1209423008/diff/20001/sky/sdk/lib/widgets/tas...
File sky/sdk/lib/widgets/task_description.dart (right):

https://codereview.chromium.org/1209423008/diff/20001/sky/sdk/lib/widgets/tas...
sky/sdk/lib/widgets/task_description.dart:10: Widget child;
these should be final, and after the constructor

https://codereview.chromium.org/1209423008/diff/20001/sky/sdk/lib/widgets/tas...
sky/sdk/lib/widgets/task_description.dart:13: TaskDescription({this.label,
this.child});
put spaces inside the {}s around the arguments