Make core Ticker abstract and public (#116)

* Make core Ticker abstract and public
Make the core Ticker abstract and public so it can be inherited by platform
implementations; remove now-unused parts of original Ticker; add CreateTicker
to IPlatformServices; remove unused CreateTimer methods from IPlatformServices

* Add docs for Ticker

* Remove unnecessary Ticker.Default set

* Move Ticker into Internals

* Update Ticker docs

* Remove old Ticker docs

* Remove commented code

2 files changed, 6 insertions, 25 deletions

diff --git a/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs b/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
index 614a0972..603ec401 100644
--- a/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
+++ b/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
@@ -17,6 +17,7 @@ using Windows.Storage.Streams;
 using Windows.System;
 using Windows.UI.Core;
 using Windows.UI.Xaml;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -28,7 +29,7 @@ namespace Xamarin.Forms.Platform.WinRT
 {
 	internal abstract class WindowsBasePlatformServices : IPlatformServices
 	{
-		 CoreDispatcher _dispatcher;
+		CoreDispatcher _dispatcher;
 
 		public WindowsBasePlatformServices(CoreDispatcher dispatcher)
 		{
@@ -43,29 +44,9 @@ namespace Xamarin.Forms.Platform.WinRT
 			_dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => action()).WatchForError();
 		}
 
-		public ITimer CreateTimer(Action<object> callback)
+		public Ticker CreateTicker()
 		{
-			return new WindowsTimer(new Timer(o => callback(o), null, Timeout.Infinite, Timeout.Infinite));
-		}
-
-		public ITimer CreateTimer(Action<object> callback, object state, int dueTime, int period)
-		{
-			return new WindowsTimer(new Timer(o => callback(o), state, dueTime, period));
-		}
-
-		public ITimer CreateTimer(Action<object> callback, object state, long dueTime, long period)
-		{
-			return CreateTimer(callback, state, TimeSpan.FromMilliseconds(dueTime), TimeSpan.FromMilliseconds(period));
-		}
-
-		public ITimer CreateTimer(Action<object> callback, object state, TimeSpan dueTime, TimeSpan period)
-		{
-			return new WindowsTimer(new Timer(o => callback(o), state, dueTime, period));
-		}
-
-		public ITimer CreateTimer(Action<object> callback, object state, uint dueTime, uint period)
-		{
-			return CreateTimer(callback, state, TimeSpan.FromMilliseconds(dueTime), TimeSpan.FromMilliseconds(period));
+			return new WindowsTicker();
 		}
 
 		public virtual Assembly[] GetAssemblies()
diff --git a/Xamarin.Forms.Platform.WinRT/WindowsTicker.cs b/Xamarin.Forms.Platform.WinRT/WindowsTicker.cs
index 2e8d941d..2599813a 100644
--- a/Xamarin.Forms.Platform.WinRT/WindowsTicker.cs
+++ b/Xamarin.Forms.Platform.WinRT/WindowsTicker.cs
@@ -1,8 +1,8 @@
 using System;
 using Windows.UI.Xaml;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
-
 namespace Xamarin.Forms.Platform.UWP
 #else
 
@@ -11,7 +11,7 @@ namespace Xamarin.Forms.Platform.WinRT
 {
 	internal class WindowsTicker : Ticker
 	{
-		 DispatcherTimer _timer;
+		readonly DispatcherTimer _timer;
 
 		public WindowsTicker()
 		{