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

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

 // Copyright (c) 2012, 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;
 
 class _ChildrenElementList extends ListBase<Element>
     implements NodeListWrapper {
   // Raw Element.
   final Element _element;
@@ skipping 1254 matching lines @@
     // offsetParent, "tops out" at BODY. But people could conceivably pass in
     // the document.documentElement and I want it to return an absolute offset,
     // so we have the special case checking for HTML.
 $if JSINTEROP
     bool sameAsParent = current == parent;
 $else
     bool sameAsParent = identical(current, parent);
 $endif
     bool foundAsParent = sameAsParent || parent.tagName == 'HTML';
     if (current == null || sameAsParent) {
-      if (foundAsParent) return new Point(0, 0);
+      if (foundAsParent) return new Point/*<num>*/(0, 0);
       throw new ArgumentError("Specified element is not a transitive offset "
           "parent of this element.");
     }
     Element parentOffset = current.offsetParent;
     Point p = Element._offsetToHelper(parentOffset, parent);
-    return new Point(p.x + current.offsetLeft, p.y + current.offsetTop);
+    return new Point/*<num>*/(p.x + current.offsetLeft, p.y + current.offsetTop);
   }
 
   static HtmlDocument _parseDocument;
   static Range _parseRange;
   static NodeValidatorBuilder _defaultValidator;
   static _ValidatingTreeSanitizer _defaultSanitizer;
 
   /**
    * Create a DocumentFragment from the HTML fragment and ensure that it follows
    * the sanitization rules specified by the validator or treeSanitizer.
@@ skipping 377 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }