Added simple functionality to remove interfaces from HTML lib.

tools/dom/scripts/systemhtml.py

Index: tools/dom/scripts/systemhtml.py
diff --git a/tools/dom/scripts/systemhtml.py b/tools/dom/scripts/systemhtml.py
index 02a4f5bfb09dd80cc208cb095c87d6f82a8b72da..796887b677e057a300283dacbe8467162377cc85 100644
--- a/tools/dom/scripts/systemhtml.py
+++ b/tools/dom/scripts/systemhtml.py
@@ -325,6 +325,10 @@ class HtmlDartInterfaceGenerator(object):
   def GenerateInterface(self):
     interface_name = self._interface_type_info.interface_name()
 
+    # Check the interface to see if should be removed.
+    if self._renamer.FindInterface(interface_name):
+      return None
+
     factory_provider = None
     if interface_name in interface_factories:
       factory_provider = interface_factories[interface_name]