Making all DOM types abstract and removing superfluous Dartium constructors.

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

Index: tools/dom/templates/html/impl/impl_Window.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Window.darttemplate b/tools/dom/templates/html/impl/impl_Window.darttemplate
index 9fead2690e7c941e7274a60b21f283a0a14c3261..fc1cbd93c04371ccf6cb968627c5a082854d40c8 100644
--- a/tools/dom/templates/html/impl/impl_Window.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Window.darttemplate
@@ -5,9 +5,9 @@
 part of $LIBRARYNAME;
 
 $if DART2JS
-$(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS native "Window,DOMWindow" {
+$(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS native "Window,DOMWindow" {
 $else
-$(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
+$(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 $endif
 
   /**
@@ -48,15 +48,15 @@ $endif
   }
 
   /**
-   * Returns a Future that completes just before the window is about to 
+   * Returns a Future that completes just before the window is about to
    * repaint so the user can draw an animation frame.
    *
    * If you need to later cancel this animation, use [requestAnimationFrame]
    * instead.
    *
    * The [Future] completes to a timestamp that represents a floating
-   * point value of the number of milliseconds that have elapsed since the page 
-   * started to load (which is also the timestamp at this call to 
+   * point value of the number of milliseconds that have elapsed since the page
+   * started to load (which is also the timestamp at this call to
    * animationFrame).
    *
    * Note: The code that runs when the future completes should call