Temporarily disable TouchList constructor to implement varargs.

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 31c2d5e14d1d39161fec8a2bfc1b0df2f60861c4..d0df6ece551406e1fe6b1195dec41bb987bf5735 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -25734,7 +25734,8 @@ class TouchList extends NativeFieldWrapperClass2 with ListMixin<Touch>, Immutabl
   /// NB: This constructor likely does not work as you might expect it to! This
   /// constructor will simply fail (returning null) if you are not on a device
   /// with touch enabled. See dartbug.com/8314.
-  factory TouchList() => document._createTouchList();
+  // TODO(5760): createTouchList now uses varargs.
+  factory TouchList() => null;//document._createTouchList();
   // To suppress missing implicit constructor warnings.
   factory TouchList._() { throw new UnsupportedError("Not supported"); }