Make the TaskDescription background color match the ToolBar on Android

sky/services/intents/intents.mojom

Index: sky/services/intents/intents.mojom
diff --git a/sky/services/intents/intents.mojom b/sky/services/intents/intents.mojom
index 6e48dd9dd811e013119938ee8574371969c5ba96..09435ec831f035d1f008d16e05f19205e76a422d 100644
--- a/sky/services/intents/intents.mojom
+++ b/sky/services/intents/intents.mojom
@@ -21,6 +21,11 @@ struct Intent {
   array<StringExtra>? string_extras;
 };
 
+struct TaskDescription {
+  string? label;
+  uint32 primaryColor;
+};
+
 // TODO(abarth): This interface seems very specific to Android. Do we want to
 //               have a higher-level abstraction here? Do we want a collection
 //               of services that only work on specific platforms? We need to
@@ -28,4 +33,5 @@ struct Intent {
 interface ActivityManager {
   startActivity(Intent intent);
   finishCurrentActivity();
+  setTaskDescription(TaskDescription description);
 };