Assume Document may be HtmlDocument

sdk/lib/_internal/lib/native_helper.dart

Index: sdk/lib/_internal/lib/native_helper.dart
diff --git a/sdk/lib/_internal/lib/native_helper.dart b/sdk/lib/_internal/lib/native_helper.dart
index 65008e41cf86e95e1541514d26e826a86219a9e9..4362a8e889c3a35f5c8d8d1bd445f6cb095d430c 100644
--- a/sdk/lib/_internal/lib/native_helper.dart
+++ b/sdk/lib/_internal/lib/native_helper.dart
@@ -389,6 +389,8 @@ void initHooks() {
   hooks = applyHooksTransformer(_operaHooksTransformer, hooks);
   hooks = applyHooksTransformer(_safariHooksTransformer, hooks);
 
+  hooks = applyHooksTransformer(_fixDocumentHooksTransformer, hooks);
+
   // TODO(sra): Update ShadowDOM polyfil to use
   // [dartNativeDispatchHooksTransformer] and remove this hook.
   hooks = applyHooksTransformer(_dartExperimentalFixupGetTagHooksTransformer,
@@ -546,14 +548,6 @@ function(hooks) {
     var tag = getTag(o);
     var newTag = quickMap[tag];
     if (newTag) return newTag;
-    if (tag == "Document") {
-      // IE calls both HTML and XML documents "Document", so we check for the
-      // xmlVersion property, which is the empty string on HTML documents.
-      // Since both dart:html classes Document and HtmlDocument share the same
-      // type, we must patch the instances and not the prototype.
-      if (!!o.xmlVersion) return "!Document";
-      return "!HTMLDocument";
-    }
     // Patches for types which report themselves as Objects.
     if (tag == "Object") {
       if (window.DataView && (o instanceof window.DataView)) return "DataView";
@@ -562,7 +556,6 @@ function(hooks) {
   }
 
   function prototypeForTagIE(tag) {
-    if (tag == "Document") return null;  // Do not pre-patch Document.
     var constructor = window[tag];
     if (constructor == null) return null;
     return constructor.prototype;
@@ -572,6 +565,32 @@ function(hooks) {
   hooks.prototypeForTag = prototypeForTagIE;
 }''');
 
+const _fixDocumentHooksTransformer = const JS_CONST(r'''
+function(hooks) {
+  var getTag = hooks.getTag;
+  var prototypeForTag = hooks.prototypeForTag;
+  function getTagFixed(o) {
+    var tag = getTag(o);
+    if (tag == "Document") {
+      // Some browsers and the polymer polyfill call both HTML and XML documents
+      // "Document", so we check for the xmlVersion property, which is the empty
+      // string on HTML documents. Since both dart:html classes Document and
+      // HtmlDocument share the same type, we must patch the instances and not
+      // the prototype.
+      if (!!o.xmlVersion) return "!Document";
+      return "!HTMLDocument";
+    }
+    return tag;
+  }
+
+  function prototypeForTagFixed(tag) {
+    if (tag == "Document") return null;  // Do not pre-patch Document.
+    return prototypeForTag(tag);
+  }
+
+  hooks.getTag = getTagFixed;
+  hooks.prototypeForTag = prototypeForTagFixed;
+}''');
 
 const _firefoxHooksTransformer = const JS_CONST(r'''
 function(hooks) {