From c03c4cca10211ad851b754f6ebcc2f17105b3290 Mon Sep 17 00:00:00 2001
From: Ian Hickson <ian@hixie.ch>
Date: Sat, 16 Jan 2016 11:43:57 -0800
Subject: [PATCH] Activity clean-up

Turns out Android crashes if the colour is not opaque, so we enforce
that at the Dart level.

Also, since label and colour are both actually optional, make them
named arguments.
---
 examples/rendering/interactive_flex.dart        |  2 +-
 packages/flutter/lib/src/services/activity.dart |  8 +++++---
 packages/flutter/lib/src/widgets/title.dart     | 12 ++++++++----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/examples/rendering/interactive_flex.dart b/examples/rendering/interactive_flex.dart
index 176a755ffc..d9c197925a 100644
--- a/examples/rendering/interactive_flex.dart
+++ b/examples/rendering/interactive_flex.dart
@@ -121,6 +121,6 @@ Pancetta meatball tongue tenderloin rump tail jowl boudin.""";
     child: row
   );
 
-  updateTaskDescription('Interactive Flex', topColor);
+  updateTaskDescription(label: 'Interactive Flex', color: topColor);
   new DemoBinding(root: root);
 }
diff --git a/packages/flutter/lib/src/services/activity.dart b/packages/flutter/lib/src/services/activity.dart
index af2f65b649..4c3feaee2e 100644
--- a/packages/flutter/lib/src/services/activity.dart
+++ b/packages/flutter/lib/src/services/activity.dart
@@ -11,7 +11,7 @@ import 'shell.dart';
 
 export 'package:sky_services/activity/activity.mojom.dart';
 
-/// Dart wrapper around Activity mojo service available in Sky on Android.
+/// Dart wrapper around Activity mojo service available in Flutter on Android.
 ///
 /// Most clients will want to use these methods instead of the activity service
 /// directly.
@@ -50,8 +50,10 @@ final PathService pathService = _pathServiceProxy.ptr;
 Color _cachedPrimaryColor;
 String _cachedLabel;
 
-/// Sets the TaskDescription for the current Activity
-void updateTaskDescription(String label, Color color) {
+/// Sets the TaskDescription for the current Activity.
+/// The color, if provided, must be opaque.
+void updateTaskDescription({ String label, Color color }) {
+  assert(color == null || color.alpha == 0xFF);
   if (_cachedPrimaryColor == color && _cachedLabel == label)
     return;
 
diff --git a/packages/flutter/lib/src/widgets/title.dart b/packages/flutter/lib/src/widgets/title.dart
index 2908a810d1..57edd8e1d1 100644
--- a/packages/flutter/lib/src/widgets/title.dart
+++ b/packages/flutter/lib/src/widgets/title.dart
@@ -7,7 +7,9 @@ import 'package:flutter/widgets.dart';
 
 /// Controls the description of this app in the operating system.
 class Title extends StatelessComponent {
-  Title({ this.title, this.child, this.color });
+  Title({ this.title, this.child, this.color }) {
+    assert(color == null || color.alpha == 0xFF);
+  }
 
   final Widget child;
 
@@ -18,13 +20,15 @@ class Title extends StatelessComponent {
   final Color color;
 
   Widget build(BuildContext context) {
-    updateTaskDescription(title, color);
+    updateTaskDescription(label: title, color: color);
     return child;
   }
 
   void debugFillDescription(List<String> description) {
     super.debugFillDescription(description);
-    description.add('"$title"');
-    description.add('color: $color');
+    if (title != null)
+      description.add('"$title"');
+    if (color != null)
+      description.add('color: $color');
   }
 }