Ink splashes should start at the touch point

sky/sdk/lib/framework/components2/ink_well.dart

Index: sky/sdk/lib/framework/components2/ink_well.dart
diff --git a/sky/sdk/lib/framework/components2/ink_well.dart b/sky/sdk/lib/framework/components2/ink_well.dart
index c793e3e24c71a995ef7a8a5d0bbb4cc01159555a..bfb18190120e25a57d642329d2a499393703d116 100644
--- a/sky/sdk/lib/framework/components2/ink_well.dart
+++ b/sky/sdk/lib/framework/components2/ink_well.dart
@@ -66,11 +66,11 @@ class RenderInkWell extends RenderProxyBox {
 
   final List<InkSplash> _splashes = new List<InkSplash>();
 
-  void handleEvent(sky.Event event) {
+  void handleEvent(sky.Event event, BoxHitTestData data) {
     switch (event.type) {
       case 'gesturetapdown':
         // TODO(abarth): We should position the splash at the location of the tap.
-        _startSplash(event.primaryPointer, new Point(size.width / 2.0, size.height / 2.0));
+        _startSplash(event.primaryPointer, data.localPosition);
         break;
       case 'gesturetap':
         _confirmSplash(event.primaryPointer);