diff --git a/content/base/public/Element.h b/content/base/public/Element.h
index 5f323e245c29..2ebdcf6be54f 100644
--- a/content/base/public/Element.h
+++ b/content/base/public/Element.h
@@ -646,6 +646,10 @@ public:
 
   already_AddRefed<DOMRectList> GetClientRects();
   already_AddRefed<DOMRect> GetBoundingClientRect();
+  void ScrollIntoView()
+  {
+    ScrollIntoView(true);
+  }
   void ScrollIntoView(bool aTop);
   int32_t ScrollTop()
   {
diff --git a/content/base/public/nsIDocument.h b/content/base/public/nsIDocument.h
index 798e117889fe..50c33fcb0178 100644
--- a/content/base/public/nsIDocument.h
+++ b/content/base/public/nsIDocument.h
@@ -2001,6 +2001,11 @@ public:
                                 mozilla::ErrorResult& rv) const;
   already_AddRefed<nsINode>
     ImportNode(nsINode& aNode, bool aDeep, mozilla::ErrorResult& rv) const;
+  already_AddRefed<nsINode>
+    ImportNode(nsINode& aNode, mozilla::ErrorResult& rv) const
+  {
+    return ImportNode(aNode, true, rv);
+  }
   nsINode* AdoptNode(nsINode& aNode, mozilla::ErrorResult& rv);
   already_AddRefed<nsDOMEvent> CreateEvent(const nsAString& aEventType,
                                            mozilla::ErrorResult& rv) const;
diff --git a/content/base/public/nsINode.h b/content/base/public/nsINode.h
index 2fbc246fd01d..a6da12d4613f 100644
--- a/content/base/public/nsINode.h
+++ b/content/base/public/nsINode.h
@@ -1533,6 +1533,10 @@ public:
     return ReplaceOrInsertBefore(true, &aNode, &aChild, aError);
   }
   nsINode* RemoveChild(nsINode& aChild, mozilla::ErrorResult& aError);
+  already_AddRefed<nsINode> CloneNode(mozilla::ErrorResult& aError)
+  {
+    return CloneNode(true, aError);
+  }
   already_AddRefed<nsINode> CloneNode(bool aDeep, mozilla::ErrorResult& aError);
   bool IsEqualNode(nsINode* aNode);
   void GetNamespaceURI(nsAString& aNamespaceURI) const
diff --git a/content/base/src/nsXMLHttpRequest.h b/content/base/src/nsXMLHttpRequest.h
index ef2eb8e50fa6..e66da6040af3 100644
--- a/content/base/src/nsXMLHttpRequest.h
+++ b/content/base/src/nsXMLHttpRequest.h
@@ -282,6 +282,13 @@ public:
   uint16_t ReadyState();
 
   // request
+  void Open(const nsACString& aMethod, const nsAString& aUrl, ErrorResult& aRv)
+  {
+    Open(aMethod, aUrl, true,
+         mozilla::dom::Optional<nsAString>(),
+         mozilla::dom::Optional<nsAString>(),
+         aRv);
+  }
   void Open(const nsACString& aMethod, const nsAString& aUrl, bool aAsync,
             const mozilla::dom::Optional<nsAString>& aUser,
             const mozilla::dom::Optional<nsAString>& aPassword,
diff --git a/content/base/test/test_createHTMLDocument.html b/content/base/test/test_createHTMLDocument.html
index 40f585b2b060..14749a2df849 100644
--- a/content/base/test/test_createHTMLDocument.html
+++ b/content/base/test/test_createHTMLDocument.html
@@ -27,11 +27,15 @@ function checkDoc(title, expectedtitle, normalizedtitle) {
   is(doc.doctype.internalSubset, null, "internalSubset should be null!");
   isElement(doc.documentElement, "html");
   isElement(doc.documentElement.firstChild, "head");
-  is(doc.documentElement.firstChild.childNodes.length, 1);
-  isElement(doc.documentElement.firstChild.firstChild, "title");
-  // Doesn't always work out in WebKit.
-  ok(doc.documentElement.firstChild.firstChild.firstChild, "Need a text node.");
-  is(doc.documentElement.firstChild.firstChild.firstChild.data, expectedtitle);
+  if (title !== undefined) {
+    is(doc.documentElement.firstChild.childNodes.length, 1);
+    isElement(doc.documentElement.firstChild.firstChild, "title");
+    // Doesn't always work out in WebKit.
+    ok(doc.documentElement.firstChild.firstChild.firstChild, "Need a text node.");
+    is(doc.documentElement.firstChild.firstChild.firstChild.data, expectedtitle);
+  } else {
+    is(doc.documentElement.firstChild.childNodes.length, 0);
+  }
   isElement(doc.documentElement.lastChild, "body");
   is(doc.documentElement.lastChild.childNodes.length, 0);
   ((!title || title.indexOf("\f") === -1) ? is : todo_is)
@@ -41,7 +45,7 @@ function checkDoc(title, expectedtitle, normalizedtitle) {
 }
 checkDoc("", "", "");
 checkDoc(null, "null", "null");
-checkDoc(undefined, "undefined", "undefined");
+checkDoc(undefined, "", "");
 checkDoc("foo  bar baz", "foo  bar baz", "foo bar baz");
 checkDoc("foo\t\tbar baz", "foo\t\tbar baz", "foo bar baz");
 checkDoc("foo\n\nbar baz", "foo\n\nbar baz", "foo bar baz");
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
index 26a1bfee17fb..ee8beec371f9 100644
--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -3348,9 +3348,6 @@ for (uint32_t i = 0; i < length; ++i) {
             "Default": "eStringify",
             "EmptyString": "eEmpty",
             "Null": "eNull",
-            # For Missing it doesn't matter what we use here, since we'll never
-            # call ConvertJSValueToString on undefined in that case.
-            "Missing": "eStringify"
         }
         if type.nullable():
             # For nullable strings null becomes a null string.
@@ -3870,11 +3867,8 @@ class CGArgumentConverter(CGThing):
             "args[${index}]"
             ).substitute(replacer)
         self.replacementVariables["mutableVal"] = self.replacementVariables["val"]
-        if argument.treatUndefinedAs == "Missing":
-            haveValueCheck = "args.hasDefined(${index})"
-        else:
-            haveValueCheck = "${index} < args.length()"
-        haveValueCheck = string.Template(haveValueCheck).substitute(replacer)
+        haveValueCheck = string.Template(
+            "args.hasDefined(${index})").substitute(replacer)
         self.replacementVariables["haveValue"] = haveValueCheck
         self.descriptorProvider = descriptorProvider
         if self.argument.optional and not self.argument.defaultValue:
diff --git a/dom/bindings/parser/WebIDL.py b/dom/bindings/parser/WebIDL.py
index f4359b247fbb..51921078fccb 100644
--- a/dom/bindings/parser/WebIDL.py
+++ b/dom/bindings/parser/WebIDL.py
@@ -401,12 +401,7 @@ class IDLObjectWithIdentifier(IDLObject):
                 if isDictionaryMember:
                     raise WebIDLError("[TreatUndefinedAs] is not allowed for "
                                       "dictionary members", [self.location])
-                if value == 'Missing':
-                    if not isOptional:
-                        raise WebIDLError("[TreatUndefinedAs=Missing] is only "
-                                          "allowed on optional arguments",
-                                          [self.location])
-                elif value == 'Null':
+                if value == 'Null':
                     if not self.type.isDOMString():
                         raise WebIDLError("[TreatUndefinedAs=Null] is only "
                                           "allowed on arguments or "
@@ -426,8 +421,8 @@ class IDLObjectWithIdentifier(IDLObject):
                                           [self.location])
                 else:
                     raise WebIDLError("[TreatUndefinedAs] must take the "
-                                      "identifiers EmptyString or Null or "
-                                      "Missing", [self.location])
+                                      "identifiers EmptyString or Null",
+                                      [self.location])
                 self.treatUndefinedAs = value
             else:
                 unhandledAttrs.append(attr)
diff --git a/dom/bindings/test/TestBindingHeader.h b/dom/bindings/test/TestBindingHeader.h
index 0f7bb01760ce..8c8ce0a0c269 100644
--- a/dom/bindings/test/TestBindingHeader.h
+++ b/dom/bindings/test/TestBindingHeader.h
@@ -161,9 +161,9 @@ public:
   void PassByte(int8_t);
   int8_t ReceiveByte();
   void PassOptionalByte(const Optional<int8_t>&);
-  void PassOptionalUndefinedMissingByte(const Optional<int8_t>&);
+  void PassOptionalByteBeforeRequired(const Optional<int8_t>&, int8_t);
   void PassOptionalByteWithDefault(int8_t);
-  void PassOptionalUndefinedMissingByteWithDefault(int8_t);
+  void PassOptionalByteWithDefaultBeforeRequired(int8_t, int8_t);
   void PassNullableByte(const Nullable<int8_t>&);
   void PassOptionalNullableByte(const Optional< Nullable<int8_t> >&);
   void PassVariadicByte(const Sequence<int8_t>&);
@@ -410,9 +410,7 @@ public:
   void PassString(const nsAString&);
   void PassNullableString(const nsAString&);
   void PassOptionalString(const Optional<nsAString>&);
-  void PassOptionalUndefinedMissingString(const Optional<nsAString>&);
   void PassOptionalStringWithDefaultValue(const nsAString&);
-  void PassOptionalUndefinedMissingStringWithDefaultValue(const nsAString&);
   void PassOptionalNullableString(const Optional<nsAString>&);
   void PassOptionalNullableStringWithDefaultValue(const nsAString&);
   void PassVariadicString(const Sequence<nsString>&);
diff --git a/dom/bindings/test/TestCodeGen.webidl b/dom/bindings/test/TestCodeGen.webidl
index 6921744765b6..b5e945c0f81d 100644
--- a/dom/bindings/test/TestCodeGen.webidl
+++ b/dom/bindings/test/TestCodeGen.webidl
@@ -118,9 +118,9 @@ interface TestInterface {
   void passByte(byte arg);
   byte receiveByte();
   void passOptionalByte(optional byte arg);
-  void passOptionalUndefinedMissingByte([TreatUndefinedAs=Missing] optional byte arg);
+  void passOptionalByteBeforeRequired(optional byte arg1, byte arg2);
   void passOptionalByteWithDefault(optional byte arg = 0);
-  void passOptionalUndefinedMissingByteWithDefault([TreatUndefinedAs=Missing] optional byte arg = 0);
+  void passOptionalByteWithDefaultBeforeRequired(optional byte arg1 = 0, byte arg2);
   void passNullableByte(byte? arg);
   void passOptionalNullableByte(optional byte? arg);
   void passVariadicByte(byte... arg);
@@ -365,9 +365,7 @@ interface TestInterface {
   void passString(DOMString arg);
   void passNullableString(DOMString? arg);
   void passOptionalString(optional DOMString arg);
-  void passOptionalUndefinedMissingString([TreatUndefinedAs=Missing] optional DOMString arg);
   void passOptionalStringWithDefaultValue(optional DOMString arg = "abc");
-  void passOptionalUndefinedMissingStringWithDefaultValue([TreatUndefinedAs=Missing] optional DOMString arg = "abc");
   void passOptionalNullableString(optional DOMString? arg);
   void passOptionalNullableStringWithDefaultValue(optional DOMString? arg = null);
   void passVariadicString(DOMString... arg);
diff --git a/dom/bindings/test/TestExampleGen.webidl b/dom/bindings/test/TestExampleGen.webidl
index 09f6cfdf9f6f..109068eab104 100644
--- a/dom/bindings/test/TestExampleGen.webidl
+++ b/dom/bindings/test/TestExampleGen.webidl
@@ -23,9 +23,9 @@ interface TestExampleInterface {
   void passByte(byte arg);
   byte receiveByte();
   void passOptionalByte(optional byte arg);
-  void passOptionalUndefinedMissingByte([TreatUndefinedAs=Missing] optional byte arg);
+  void passOptionalByteBeforeRequired(optional byte arg1, byte arg2);
   void passOptionalByteWithDefault(optional byte arg = 0);
-  void passOptionalUndefinedMissingByteWithDefault([TreatUndefinedAs=Missing] optional byte arg = 0);
+  void passOptionalByteWithDefaultBeforeRequired(optional byte arg1 = 0, byte arg2);
   void passNullableByte(byte? arg);
   void passOptionalNullableByte(optional byte? arg);
   void passVariadicByte(byte... arg);
@@ -263,9 +263,7 @@ interface TestExampleInterface {
   void passString(DOMString arg);
   void passNullableString(DOMString? arg);
   void passOptionalString(optional DOMString arg);
-  void passOptionalUndefinedMissingString([TreatUndefinedAs=Missing] optional DOMString arg);
   void passOptionalStringWithDefaultValue(optional DOMString arg = "abc");
-  void passOptionalUndefinedMissingStringWithDefaultValue([TreatUndefinedAs=Missing] optional DOMString arg = "abc");
   void passOptionalNullableString(optional DOMString? arg);
   void passOptionalNullableStringWithDefaultValue(optional DOMString? arg = null);
   void passVariadicString(DOMString... arg);
diff --git a/dom/bindings/test/TestJSImplGen.webidl b/dom/bindings/test/TestJSImplGen.webidl
index 17c0f5ea7fa0..a4a48e131f06 100644
--- a/dom/bindings/test/TestJSImplGen.webidl
+++ b/dom/bindings/test/TestJSImplGen.webidl
@@ -35,9 +35,9 @@ interface TestJSImplInterface {
   void passByte(byte arg);
   byte receiveByte();
   void passOptionalByte(optional byte arg);
-  void passOptionalUndefinedMissingByte([TreatUndefinedAs=Missing] optional byte arg);
+  void passOptionalByteBeforeRequired(optional byte arg1, byte arg2);
   void passOptionalByteWithDefault(optional byte arg = 0);
-  void passOptionalUndefinedMissingByteWithDefault([TreatUndefinedAs=Missing] optional byte arg = 0);
+  void passOptionalByteWithDefaultBeforeRequired(optional byte arg1 = 0, byte arg2);
   void passNullableByte(byte? arg);
   void passOptionalNullableByte(optional byte? arg);
   void passVariadicByte(byte... arg);
@@ -285,9 +285,7 @@ interface TestJSImplInterface {
   void passString(DOMString arg);
   void passNullableString(DOMString? arg);
   void passOptionalString(optional DOMString arg);
-  void passOptionalUndefinedMissingString([TreatUndefinedAs=Missing] optional DOMString arg);
   void passOptionalStringWithDefaultValue(optional DOMString arg = "abc");
-  void passOptionalUndefinedMissingStringWithDefaultValue([TreatUndefinedAs=Missing] optional DOMString arg = "abc");
   void passOptionalNullableString(optional DOMString? arg);
   void passOptionalNullableStringWithDefaultValue(optional DOMString? arg = null);
   void passVariadicString(DOMString... arg);
diff --git a/dom/bindings/test/mochitest.ini b/dom/bindings/test/mochitest.ini
index a93f7a1fea10..3b019305bd7d 100644
--- a/dom/bindings/test/mochitest.ini
+++ b/dom/bindings/test/mochitest.ini
@@ -16,6 +16,7 @@ support-files =
 [test_bug788369.html]
 [test_bug852846.html]
 [test_bug862092.html]
+[test_cloneAndImportNode.html]
 [test_defineProperty.html]
 [test_enums.html]
 [test_exceptionThrowing.html]
diff --git a/dom/bindings/test/test_cloneAndImportNode.html b/dom/bindings/test/test_cloneAndImportNode.html
new file mode 100644
index 000000000000..d173131a7ced
--- /dev/null
+++ b/dom/bindings/test/test_cloneAndImportNode.html
@@ -0,0 +1,42 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=882541
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 882541</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 882541 **/
+  var div = document.createElement("div");
+  div.appendChild(document.createElement("span"));
+
+  var div2;
+
+  div2 = div.cloneNode();
+  is(div2.childNodes.length, 1, "cloneNode() should do a deep clone");
+
+  div2 = div.cloneNode(undefined);
+  is(div2.childNodes.length, 0, "cloneNode(undefined) should do a shallow clone");
+
+  div2 = document.importNode(div);
+  is(div2.childNodes.length, 1, "importNode(node) should do a deep import");
+
+  div2 = document.importNode(div, undefined);
+  is(div2.childNodes.length, 0, "cloneNode(undefined) should do a shallow import");
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=882541">Mozilla Bug 882541</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/dom/imptests/html/dom/nodes/test_DOMImplementation-createHTMLDocument.html b/dom/imptests/html/dom/nodes/test_DOMImplementation-createHTMLDocument.html
index d80482817974..12d1bb76e85f 100644
--- a/dom/imptests/html/dom/nodes/test_DOMImplementation-createHTMLDocument.html
+++ b/dom/imptests/html/dom/nodes/test_DOMImplementation-createHTMLDocument.html
@@ -18,17 +18,21 @@ function checkDoc(title, expectedtitle, normalizedtitle) {
     assert_equals(doc.doctype.systemId, "")
     assert_equals(doc.documentElement.localName, "html")
     assert_equals(doc.documentElement.firstChild.localName, "head")
-    assert_equals(doc.documentElement.firstChild.childNodes.length, 1)
-    assert_equals(doc.documentElement.firstChild.firstChild.localName, "title")
-    assert_equals(doc.documentElement.firstChild.firstChild.firstChild.data,
-    expectedtitle)
+    if (title !== undefined) {
+      assert_equals(doc.documentElement.firstChild.childNodes.length, 1)
+      assert_equals(doc.documentElement.firstChild.firstChild.localName, "title")
+      assert_equals(doc.documentElement.firstChild.firstChild.firstChild.data,
+                    expectedtitle)
+    } else {
+      assert_equals(doc.documentElement.firstChild.childNodes.length, 0)
+    }
     assert_equals(doc.documentElement.lastChild.localName, "body")
     assert_equals(doc.documentElement.lastChild.childNodes.length, 0)
   })
 }
 checkDoc("", "", "")
 checkDoc(null, "null", "null")
-checkDoc(undefined, "undefined", "undefined")
+checkDoc(undefined, "", "")
 checkDoc("foo  bar baz", "foo  bar baz", "foo bar baz")
 checkDoc("foo\t\tbar baz", "foo\t\tbar baz", "foo bar baz")
 checkDoc("foo\n\nbar baz", "foo\n\nbar baz", "foo bar baz")
diff --git a/dom/imptests/html/html/dom/documents/dta/test_document.title-07.html b/dom/imptests/html/html/dom/documents/dta/test_document.title-07.html
index ad6e7111d27a..eea97c9ede1b 100644
--- a/dom/imptests/html/html/dom/documents/dta/test_document.title-07.html
+++ b/dom/imptests/html/html/dom/documents/dta/test_document.title-07.html
@@ -12,7 +12,7 @@ function checkDoc(title, expectedtitle, normalizedtitle) {
 }
 checkDoc("", "", "")
 checkDoc(null, "null", "null")
-checkDoc(undefined, "undefined", "undefined")
+checkDoc(undefined, "", "")
 checkDoc("foo  bar baz", "foo  bar baz", "foo bar baz")
 checkDoc("foo\t\tbar baz", "foo\t\tbar baz", "foo bar baz")
 checkDoc("foo\n\nbar baz", "foo\n\nbar baz", "foo bar baz")
diff --git a/dom/webidl/CanvasRenderingContext2D.webidl b/dom/webidl/CanvasRenderingContext2D.webidl
index cf1914b06d29..de8f5155115e 100644
--- a/dom/webidl/CanvasRenderingContext2D.webidl
+++ b/dom/webidl/CanvasRenderingContext2D.webidl
@@ -73,7 +73,7 @@ interface CanvasRenderingContext2D {
 
   // path API (see also CanvasPathMethods)
   void beginPath();
-  void fill([TreatUndefinedAs=Missing] optional CanvasWindingRule winding = "nonzero");
+  void fill(optional CanvasWindingRule winding = "nonzero");
 // NOT IMPLEMENTED  void fill(Path path);
   void stroke();
 // NOT IMPLEMENTED  void stroke(Path path);
@@ -83,10 +83,10 @@ interface CanvasRenderingContext2D {
 // NOT IMPLEMENTED  boolean drawCustomFocusRing(Path path, Element element);
 // NOT IMPLEMENTED  void scrollPathIntoView();
 // NOT IMPLEMENTED  void scrollPathIntoView(Path path);
-  void clip([TreatUndefinedAs=Missing] optional CanvasWindingRule winding = "nonzero");
+  void clip(optional CanvasWindingRule winding = "nonzero");
 // NOT IMPLEMENTED  void clip(Path path);
 // NOT IMPLEMENTED  void resetClip();
-  boolean isPointInPath(unrestricted double x, unrestricted double y, [TreatUndefinedAs=Missing] optional CanvasWindingRule winding = "nonzero");
+  boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasWindingRule winding = "nonzero");
 // NOT IMPLEMENTED  boolean isPointInPath(Path path, unrestricted double x, unrestricted double y);
   boolean isPointInStroke(double x, double y);
 
diff --git a/dom/webidl/Document.webidl b/dom/webidl/Document.webidl
index 6f24026b98dd..1520239d0e33 100644
--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -54,7 +54,9 @@ interface Document : Node {
   ProcessingInstruction createProcessingInstruction(DOMString target, DOMString data);
 
   [Throws]
-  Node importNode(Node node, optional boolean deep = true);
+  Node importNode(Node node, boolean deep);
+  [Throws]
+  Node importNode(Node node);
   [Throws]
   Node adoptNode(Node node);
 
diff --git a/dom/webidl/Element.webidl b/dom/webidl/Element.webidl
index 266b8cfd535c..1e741312ef91 100644
--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -141,7 +141,8 @@ partial interface Element {
   DOMRect getBoundingClientRect();
 
   // scrolling
-  void scrollIntoView(optional boolean top = true);
+  void scrollIntoView();
+  void scrollIntoView(boolean top);
   // None of the CSSOM attributes are [Pure], because they flush
            attribute long scrollTop;   // scroll on setting
            attribute long scrollLeft;  // scroll on setting
diff --git a/dom/webidl/Node.webidl b/dom/webidl/Node.webidl
index cddd9a47a65d..d89d18c7ddd3 100644
--- a/dom/webidl/Node.webidl
+++ b/dom/webidl/Node.webidl
@@ -68,7 +68,9 @@ interface Node : EventTarget {
   void normalize();
 
   [Throws]
-  Node cloneNode(optional boolean deep = true);
+  Node cloneNode();
+  [Throws]
+  Node cloneNode(boolean deep);
   boolean isEqualNode(Node? node);
 
   const unsigned short DOCUMENT_POSITION_DISCONNECTED = 0x01;
diff --git a/dom/webidl/Promise.webidl b/dom/webidl/Promise.webidl
index 9d9d1a19aeec..8cea8a33aff0 100644
--- a/dom/webidl/Promise.webidl
+++ b/dom/webidl/Promise.webidl
@@ -28,9 +28,9 @@ interface Promise {
   static Promise reject(any value);
 
   [NewObject]
-  Promise then([TreatUndefinedAs=Missing] optional AnyCallback fulfillCallback,
-               [TreatUndefinedAs=Missing] optional AnyCallback rejectCallback);
+  Promise then(optional AnyCallback fulfillCallback,
+               optional AnyCallback rejectCallback);
 
   [NewObject]
-  Promise catch([TreatUndefinedAs=Missing] optional AnyCallback rejectCallback);
+  Promise catch(optional AnyCallback rejectCallback);
 };
diff --git a/dom/webidl/XMLHttpRequest.webidl b/dom/webidl/XMLHttpRequest.webidl
index 16dee05baa9d..ba20b72ca0f7 100644
--- a/dom/webidl/XMLHttpRequest.webidl
+++ b/dom/webidl/XMLHttpRequest.webidl
@@ -71,7 +71,9 @@ interface XMLHttpRequest : XMLHttpRequestEventTarget {
 
   // request
   [Throws]
-  void open(ByteString method, DOMString url, optional boolean async = true,
+  void open(ByteString method, DOMString url);
+  [Throws]
+  void open(ByteString method, DOMString url, boolean async,
             optional DOMString? user, optional DOMString? password);
   [Throws]
   void setRequestHeader(ByteString header, ByteString value);
diff --git a/dom/workers/XMLHttpRequest.h b/dom/workers/XMLHttpRequest.h
index 29ba0536ccc4..85616f8361a7 100644
--- a/dom/workers/XMLHttpRequest.h
+++ b/dom/workers/XMLHttpRequest.h
@@ -121,6 +121,11 @@ public:
     return mStateData.mReadyState;
   }
 
+  void Open(const nsACString& aMethod, const nsAString& aUrl, ErrorResult& aRv)
+  {
+    Open(aMethod, aUrl, true, Optional<nsAString>(),
+         Optional<nsAString>(), aRv);
+  }
   void
   Open(const nsACString& aMethod, const nsAString& aUrl, bool aAsync,
        const Optional<nsAString>& aUser, const Optional<nsAString>& aPassword,
diff --git a/js/xpconnect/tests/unit/test_allowedDomainsXHR.js b/js/xpconnect/tests/unit/test_allowedDomainsXHR.js
index 7d257c5a9ad9..387a34c1e9cf 100644
--- a/js/xpconnect/tests/unit/test_allowedDomainsXHR.js
+++ b/js/xpconnect/tests/unit/test_allowedDomainsXHR.js
@@ -52,7 +52,7 @@ function run_test()
   // Test sync XHR sending
   cu.evalInSandbox('var createXHR = ' + createXHR.toString(), sb);
   var res = cu.evalInSandbox('var sync = createXHR("4444/simple"); sync.send(null); sync', sb);
-  checkResults(res);
+  do_check_true(checkResults(res));
 
   // negative test sync XHR sending (to ensure that the xhr do not have chrome caps, see bug 779821)
   try {