Tighted type of 'document' to HtmlDocument

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

Index: tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
index a8940cbf92aa6989d9dafaf75176e0b333bc31c4..96f40a9901376977cae15631202eea827cb7b6fb 100644
--- a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
@@ -9,12 +9,7 @@ part of $LIBRARYNAME;
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 $!MEMBERS
   @DomName('Document.body')
-  BodyElement get body => document.$dom_body;
-
-  @DomName('Document.body')
-  void set body(BodyElement value) {
-    document.$dom_body = value;
-  }
+  BodyElement body;
 
   @DomName('Document.caretRangeFromPoint')
   Range caretRangeFromPoint(int x, int y) {