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

tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate

Index: tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate
diff --git a/tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate b/tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate
index 1b2bbc8dcb35d5d073cfc6864742c222e88dd7e8..229afe623fc25ff829e3616e5e8af12b94720d86 100644
--- a/tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate
+++ b/tools/dom/templates/html/dartium/impl_MouseEvent.darttemplate
@@ -43,14 +43,14 @@ $!MEMBERS
 
   @DomName('MouseEvent.clientX')
   @DomName('MouseEvent.clientY')
-  Point get client => new Point(_clientX, _clientY);
+  Point get client => new Point/*<num>*/(_clientX, _clientY);
 
   @DomName('MouseEvent.movementX')
   @DomName('MouseEvent.movementY')
   @SupportedBrowser(SupportedBrowser.CHROME)
   @SupportedBrowser(SupportedBrowser.FIREFOX)
   @Experimental()
-  Point get movement => new Point(_movementX, _movementY);
+  Point get movement => new Point/*<num>*/(_movementX, _movementY);
 
   /**
    * The coordinates of the mouse pointer in target node coordinates.
@@ -59,17 +59,17 @@ $!MEMBERS
    * after the event has fired or if the element has CSS transforms affecting
    * it.
    */
-  Point get offset => new Point(_offsetX, _offsetY);
+  Point get offset => new Point/*<num>*/(_offsetX, _offsetY);
 
   @DomName('MouseEvent.screenX')
   @DomName('MouseEvent.screenY')
-  Point get screen => new Point(_screenX, _screenY);
+  Point get screen => new Point/*<num>*/(_screenX, _screenY);
 
   @DomName('MouseEvent.layerX')
   @DomName('MouseEvent.layerY')
-  Point get layer => new Point(_layerX, _layerY);
+  Point get layer => new Point/*<num>*/(_layerX, _layerY);
 
   @DomName('MouseEvent.pageX')
   @DomName('MouseEvent.pageY')
-  Point get page => new Point(_pageX, _pageY);
+  Point get page => new Point/*<num>*/(_pageX, _pageY);
 }