Use Point<num> in dart:html for strong mode

tools/dom/templates/html/impl/impl_DOMRectReadOnly.darttemplate

 // 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 $LIBRARYNAME;
 
 @DocsEditable()
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS implements Rectangle$IMPLEMENTS {
 
   // NOTE! All code below should be common with RectangleBase.
@@ skipping 71 matching lines @@
   /**
    * Tests whether [another] is inside or along the edges of `this`.
    */
   bool containsPoint(Point<num> another) {
     return another.x >= left &&
            another.x <= left + width &&
            another.y >= top &&
            another.y <= top + height;
   }
 
-  Point get topLeft => new Point(this.left, this.top);
-  Point get topRight => new Point(this.left + this.width, this.top);
-  Point get bottomRight => new Point(this.left + this.width,
+  Point get topLeft => new Point/*<num>*/(this.left, this.top);
+  Point get topRight => new Point/*<num>*/(this.left + this.width, this.top);
+  Point get bottomRight => new Point/*<num>*/(this.left + this.width,
       this.top + this.height);
-  Point get bottomLeft => new Point(this.left,
+  Point get bottomLeft => new Point/*<num>*/(this.left,
       this.top + this.height);
 
   $!MEMBERS}