Merge pull request #457 from eseidelGoogle/docs

Add a few bits of documentation to package:sky

packages/flutter/lib/mojo/activity.dart

@@ -9,6 +9,11 @@ import 'package:sky_services/activity/activity.mojom.dart';
 
 export 'package:sky_services/activity/activity.mojom.dart' show Intent, ComponentName, StringExtra;
 
+/// Dart wrapper around Activity mojo service available in Sky on Android.
+///
+/// Most clients will want to use these methods instead of the activity service
+/// directly.
+
 const int NEW_DOCUMENT = 0x00080000;
 const int NEW_TASK = 0x10000000;
 const int MULTIPLE_TASK = 0x08000000;
@@ -24,15 +29,17 @@ final ActivityProxy _activity = _initActivity();
 Color _cachedPrimaryColor;
 String _cachedLabel;
 
-
+/// Ends the current activity.
 void finishCurrentActivity() {
   _activity.ptr.finishCurrentActivity();
 }
 
+/// Asks the Android ActivityManager to start a new Intent-based Activity.
 void startActivity(Intent intent) {
   _activity.ptr.startActivity(intent);
 }
 
+/// Sets the TaskDescription for the current Activity
 void updateTaskDescription(String label, Color color) {
   if (_cachedPrimaryColor == color && _cachedLabel == label)
     return;

packages/flutter/lib/widgets.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// Includes and re-exports all Sky widgets classes.
+
 export 'widgets/animated_component.dart';
 export 'widgets/animated_container.dart';
 export 'widgets/basic.dart';