Fix undefined method errors adding no-op stubs for methods needed by dart2js but irrelevant in ddc.…

tool/input_sdk/private/native_helper.dart

Index: tool/input_sdk/private/native_helper.dart
diff --git a/tool/input_sdk/private/native_helper.dart b/tool/input_sdk/private/native_helper.dart
index 2edaa4d4a4431f1e0c73490879cf2dbfabab7d17..de77f66713e342b445ae49b1b60202fcf6059a93 100644
--- a/tool/input_sdk/private/native_helper.dart
+++ b/tool/input_sdk/private/native_helper.dart
@@ -16,3 +16,16 @@ void defineProperty(var obj, String property, var value) {
       property,
       value);
 }
+
+// Obsolete in dart dev compiler. Added only so that the same version of
+// dart:html can be used in dart2js an dev compiler.
+/*=F*/ convertDartClosureToJS /*<F>*/ (/*=F*/ closure, int arity) {
+	return closure;
+}
+
+// Warning: calls to these methods need to be removed before custom elements
+// and cross-frame dom objects behave correctly in ddc.
+// See https://github.com/dart-lang/dev_compiler/issues/517
+setNativeSubclassDispatchRecord(proto, interceptor) { }
+findDispatchTagForInterceptorClass(interceptorClassConstructor) {}
+makeLeafDispatchRecord(interceptor) {}