Generation of sdk/lib files from 45 roll

tools/dom/scripts/htmldartgenerator.py

Index: tools/dom/scripts/htmldartgenerator.py
diff --git a/tools/dom/scripts/htmldartgenerator.py b/tools/dom/scripts/htmldartgenerator.py
index b93b0ca9ebdd905b1c1b8a5cd2365bbab33a7084..c944fc3e99e9ea11ac064f3078d5807e8e2b14ed 100644
--- a/tools/dom/scripts/htmldartgenerator.py
+++ b/tools/dom/scripts/htmldartgenerator.py
@@ -132,6 +132,13 @@ class HtmlDartGenerator(object):
 
     secondary_parents = self._database.TransitiveSecondaryParents(interface,
                           not self._dart_use_blink)
+    remove_duplicate_parents = list(set(secondary_parents))
+    if len(secondary_parents) != len(remove_duplicate_parents):
+      secondary_parents = remove_duplicate_parents
+      parent_list = ", ".join(["  %s" % (parent.id) for parent in secondary_parents])
+      _logger.warn('Interface %s has duplicate parent interfaces %s - ' \
+                   'ignoring duplicates. Please file a bug with the dart:html team.' % (interface.id, parent_list))
+
     for parent_interface in sorted(secondary_parents):
       if isinstance(parent_interface, str):
         continue