Make dart:math strong mode clean.

sdk/lib/math/point.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 part of dart.math;
 
 /**
  * A utility class for representing two-dimensional positions.
  */
 class Point<T extends num> {
   final T x;
@@ skipping 37 matching lines @@
 
   /**
    * Scale this point by [factor] as if it were a vector.
    *
    * *Important* *Note*: This function accepts a `num` as its argument only so
    * that you can scale Point<double> objects by an `int` factor. Because the
    * star operator always returns the same type of Point that originally called
    * it, passing in a double [factor] on a `Point<int>` _causes_ _a_
    * _runtime_ _error_ in checked mode.
    */
-  Point<T> operator *(num factor) {
-    return new Point<T>(x * factor, y * factor);
+  Point<T> operator *(num/*T|int*/ factor) {
+    return new Point<T>(
+        (x * factor) as dynamic/*=T*/, (y * factor) as dynamic/*=T*/);
   }
 
   /**
    * Get the straight line (Euclidean) distance between the origin (0, 0) and
    * this point.
    */
   double get magnitude => sqrt(x * x + y * y);
 
   /**
    * Returns the distance between `this` and [other].
    */
   double distanceTo(Point<T> other) {
     var dx = x - other.x;
     var dy = y - other.y;
     return sqrt(dx * dx + dy * dy);
   }
 
   /**
    * Returns the squared distance between `this` and [other].
    *
    * Squared distances can be used for comparisons when the actual value is not
    * required.
    */
   T squaredDistanceTo(Point<T> other) {
     var dx = x - other.x;
     var dy = y - other.y;
     return dx * dx + dy * dy;
   }
 }