Do not treat callbacks with no handlers as interfaces.

lib/dom/scripts/generator.py

Index: lib/dom/scripts/generator.py
diff --git a/lib/dom/scripts/generator.py b/lib/dom/scripts/generator.py
index fd758185139ed8fbe841a7de2fa20d655acbcc25..89536907d2ae823913153bec5f19416fd9d1d882 100644
--- a/lib/dom/scripts/generator.py
+++ b/lib/dom/scripts/generator.py
@@ -306,17 +306,6 @@ def AnalyzeConstructor(interface):
   info.param_infos = args
   return info
 
-
-def RecognizeCallback(interface):
-  """Returns the info for the callback method if the interface smells like a
-  callback.
-  """
-  if 'Callback' not in interface.ext_attrs: return None
-  handlers = [op for op in interface.operations if op.id == 'handleEvent']
-  if not handlers: return None
-  if not (handlers == interface.operations): return None
-  return AnalyzeOperation(interface, handlers)
-
 def IsDartListType(type):
   return type == 'List' or type.startswith('sequence<')