Make WheelEvent.delta{X,Y} return num, not int.

lib/html/scripts/systemhtml.py

Index: lib/html/scripts/systemhtml.py
diff --git a/lib/html/scripts/systemhtml.py b/lib/html/scripts/systemhtml.py
index bedffc413aa8723f577c70661a76143c243eb6ac..83deee6794c897f13e47b885b04337fd5066e14e 100644
--- a/lib/html/scripts/systemhtml.py
+++ b/lib/html/scripts/systemhtml.py
@@ -460,30 +460,31 @@ class HtmlDartInterfaceGenerator(object):
     dom_name = DartDomNameOfAttribute(attribute)
     html_name = self._renamer.RenameMember(
       self._interface.id, dom_name, 'get:')
-    if not html_name or self._IsPrivate(html_name):
+    if not html_name:
       return
 
-
     html_setter_name = self._renamer.RenameMember(
         self._interface.id, dom_name, 'set:')
     read_only = (attribute.is_read_only or 'Replaceable' in attribute.ext_attrs
                  or not html_setter_name)
 
-    # We don't yet handle inconsistent renames of the getter and setter yet.
-    assert(not html_setter_name or html_name == html_setter_name)
+    if not self._IsPrivate(html_name):
 
-    if not is_secondary:
-      self._members_emitter.Emit('\n  /** @domName $DOMINTERFACE.$DOMNAME */',
-          DOMINTERFACE=attribute.doc_js_interface_name,
-          DOMNAME=dom_name)
-      if read_only:
-        template = '\n  abstract $TYPE get $NAME;\n'
-      else:
-        template = '\n  $TYPE $NAME;\n'
+      # We don't yet handle inconsistent renames of the getter and setter yet.
+      assert(not html_setter_name or html_name == html_setter_name)
+
+      if not is_secondary:
+        self._members_emitter.Emit('\n  /** @domName $DOMINTERFACE.$DOMNAME */',
+            DOMINTERFACE=attribute.doc_js_interface_name,
+            DOMNAME=dom_name)
+        if read_only:
+          template = '\n  abstract $TYPE get $NAME;\n'
+        else:
+          template = '\n  $TYPE $NAME;\n'
 
-      self._members_emitter.Emit(template,
-                                 NAME=html_name,
-                                 TYPE=SecureOutputType(self, attribute.type.id))
+        self._members_emitter.Emit(template,
+                                  NAME=html_name,
+                                  TYPE=SecureOutputType(self, attribute.type.id))
 
     self._backend.AddAttribute(attribute, html_name, read_only)