Revert 20127

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

Index: tools/dom/templates/html/impl/impl_MutationObserver.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_MutationObserver.darttemplate b/tools/dom/templates/html/impl/impl_MutationObserver.darttemplate
index 7a107efaa4066b0464b5d52042fa3c1a2cc17f02..abab691a6794014cebf06fa6da148a0200cc44aa 100644
--- a/tools/dom/templates/html/impl/impl_MutationObserver.darttemplate
+++ b/tools/dom/templates/html/impl/impl_MutationObserver.darttemplate
@@ -20,7 +20,8 @@ $endif
   }
 
   void observe(Node target,
-               {bool childList,
+               {Map options,
+                bool childList,
                 bool attributes,
                 bool characterData,
                 bool subtree,
@@ -31,6 +32,19 @@ $endif
     // Parse options into map of known type.
     var parsedOptions = _createDict();
 
+    if (options != null) {
+      options.forEach((k, v) {
+          if (_boolKeys.containsKey(k)) {
+            _add(parsedOptions, k, true == v);
+          } else if (k == 'attributeFilter') {
+            _add(parsedOptions, k, _fixupList(v));
+          } else {
+            throw new ArgumentError(
+                "Illegal MutationObserver.observe option '$k'");
+          }
+        });
+    }
+
     // Override options passed in the map with named optional arguments.
     override(key, value) {
       if (value != null) _add(parsedOptions, key, value);