diff --git a/content/base/src/ThirdPartyUtil.cpp b/content/base/src/ThirdPartyUtil.cpp
index b195af9f48e6..ebe7ebdc6019 100644
--- a/content/base/src/ThirdPartyUtil.cpp
+++ b/content/base/src/ThirdPartyUtil.cpp
@@ -57,46 +57,6 @@ ThirdPartyUtil::Init()
   return rv;
 }
 
-// Get the base domain for aHostURI; e.g. for "www.bbc.co.uk", this would be
-// "bbc.co.uk". Only properly-formed URI's are tolerated, though a trailing
-// dot may be present. If aHostURI is an IP address, an alias such as
-// 'localhost', an eTLD such as 'co.uk', or the empty string, aBaseDomain will
-// be the exact host. The result of this function should only be used in exact
-// string comparisons, since substring comparisons will not be valid for the
-// special cases elided above.
-nsresult
-ThirdPartyUtil::GetBaseDomain(nsIURI* aHostURI,
-                              nsCString& aBaseDomain)
-{
-  // Get the base domain. this will fail if the host contains a leading dot,
-  // more than one trailing dot, or is otherwise malformed.
-  nsresult rv = mTLDService->GetBaseDomain(aHostURI, 0, aBaseDomain);
-  if (rv == NS_ERROR_HOST_IS_IP_ADDRESS ||
-      rv == NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS) {
-    // aHostURI is either an IP address, an alias such as 'localhost', an eTLD
-    // such as 'co.uk', or the empty string. Uses the normalized host in such
-    // cases.
-    rv = aHostURI->GetAsciiHost(aBaseDomain);
-  }
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  // aHostURI (and thus aBaseDomain) may be the string '.'. If so, fail.
-  if (aBaseDomain.Length() == 1 && aBaseDomain.Last() == '.')
-    return NS_ERROR_INVALID_ARG;
-
-  // Reject any URIs without a host that aren't file:// URIs. This makes it the
-  // only way we can get a base domain consisting of the empty string, which
-  // means we can safely perform foreign tests on such URIs where "not foreign"
-  // means "the involved URIs are all file://".
-  if (aBaseDomain.IsEmpty()) {
-    PRBool isFileURI = PR_FALSE;
-    aHostURI->SchemeIs("file", &isFileURI);
-    NS_ENSURE_TRUE(isFileURI, NS_ERROR_INVALID_ARG);
-  }
-
-  return NS_OK;
-}
-
 // Determine if aFirstDomain is a different base domain to aSecondURI; or, if
 // the concept of base domain does not apply, determine if the two hosts are not
 // string-identical.
@@ -316,3 +276,42 @@ ThirdPartyUtil::IsThirdPartyChannel(nsIChannel* aChannel,
   return IsThirdPartyWindow(ourWin, channelURI, aResult);
 }
 
+// Get the base domain for aHostURI; e.g. for "www.bbc.co.uk", this would be
+// "bbc.co.uk". Only properly-formed URI's are tolerated, though a trailing
+// dot may be present. If aHostURI is an IP address, an alias such as
+// 'localhost', an eTLD such as 'co.uk', or the empty string, aBaseDomain will
+// be the exact host. The result of this function should only be used in exact
+// string comparisons, since substring comparisons will not be valid for the
+// special cases elided above.
+NS_IMETHODIMP
+ThirdPartyUtil::GetBaseDomain(nsIURI* aHostURI,
+                              nsACString& aBaseDomain)
+{
+  // Get the base domain. this will fail if the host contains a leading dot,
+  // more than one trailing dot, or is otherwise malformed.
+  nsresult rv = mTLDService->GetBaseDomain(aHostURI, 0, aBaseDomain);
+  if (rv == NS_ERROR_HOST_IS_IP_ADDRESS ||
+      rv == NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS) {
+    // aHostURI is either an IP address, an alias such as 'localhost', an eTLD
+    // such as 'co.uk', or the empty string. Uses the normalized host in such
+    // cases.
+    rv = aHostURI->GetAsciiHost(aBaseDomain);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // aHostURI (and thus aBaseDomain) may be the string '.'. If so, fail.
+  if (aBaseDomain.Length() == 1 && aBaseDomain.Last() == '.')
+    return NS_ERROR_INVALID_ARG;
+
+  // Reject any URIs without a host that aren't file:// URIs. This makes it the
+  // only way we can get a base domain consisting of the empty string, which
+  // means we can safely perform foreign tests on such URIs where "not foreign"
+  // means "the involved URIs are all file://".
+  if (aBaseDomain.IsEmpty()) {
+    PRBool isFileURI = PR_FALSE;
+    aHostURI->SchemeIs("file", &isFileURI);
+    NS_ENSURE_TRUE(isFileURI, NS_ERROR_INVALID_ARG);
+  }
+
+  return NS_OK;
+}
diff --git a/content/base/src/ThirdPartyUtil.h b/content/base/src/ThirdPartyUtil.h
index 85cb84902e6f..164f13e6e696 100644
--- a/content/base/src/ThirdPartyUtil.h
+++ b/content/base/src/ThirdPartyUtil.h
@@ -56,7 +56,6 @@ public:
   nsresult Init();
 
 private:
-  nsresult GetBaseDomain(nsIURI* aHostURI, nsCString& aBaseDomain);
   nsresult IsThirdPartyInternal(const nsCString& aFirstDomain,
     nsIURI* aSecondURI, PRBool* aResult);
   static already_AddRefed<nsIURI> GetURIFromWindow(nsIDOMWindow* aWin);
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index 07d0d0afb724..db58af4d4306 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -39,11 +39,11 @@
 
 #include "WorkerPrivate.h"
 
+#include "mozIThirdPartyUtil.h"
 #include "nsIClassInfo.h"
 #include "nsIConsoleService.h"
 #include "nsIDOMFile.h"
 #include "nsIDocument.h"
-#include "nsIEffectiveTLDService.h"
 #include "nsIJSContextStack.h"
 #include "nsIMemoryReporter.h"
 #include "nsIScriptError.h"
@@ -2329,14 +2329,14 @@ WorkerPrivate::Create(JSContext* aCx, JSObject* aObj, WorkerPrivate* aParent,
           domain = file;
         }
         else {
-          nsCOMPtr<nsIEffectiveTLDService> tldService =
-            do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);
-          if (!tldService) {
-            JS_ReportError(aCx, "Could not get TLD service!");
+          nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
+            do_GetService(THIRDPARTYUTIL_CONTRACTID);
+          if (!thirdPartyUtil) {
+            JS_ReportError(aCx, "Could not get third party helper service!");
             return nsnull;
           }
 
-          if (NS_FAILED(tldService->GetBaseDomain(codebase, 0, domain))) {
+          if (NS_FAILED(thirdPartyUtil->GetBaseDomain(codebase, domain))) {
             JS_ReportError(aCx, "Could not get domain!");
             return nsnull;
           }
diff --git a/dom/workers/test/Makefile.in b/dom/workers/test/Makefile.in
index e55f944c9eff..dba82ac982ab 100644
--- a/dom/workers/test/Makefile.in
+++ b/dom/workers/test/Makefile.in
@@ -58,6 +58,9 @@ _TEST_FILES = \
   errorPropagation_worker.js \
   test_eventDispatch.html \
   eventDispatch_worker.js \
+  test_ipAddressOrigin.html \
+  ipAddressOrigin_iframe.html \
+  ipAddressOrigin_worker.js \
   test_importScripts.html \
   importScripts_worker.js \
   importScripts_worker_imported1.js \
diff --git a/dom/workers/test/ipAddressOrigin_iframe.html b/dom/workers/test/ipAddressOrigin_iframe.html
new file mode 100644
index 000000000000..66a9f2c0cc0c
--- /dev/null
+++ b/dom/workers/test/ipAddressOrigin_iframe.html
@@ -0,0 +1,23 @@
+<!--
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<!DOCTYPE HTML>
+<html>
+<body>
+<script>
+
+  onmessage = function (event) {
+    var url = "http://127.0.0.1" +
+      window.location.pathname.replace("ipAddressOrigin_iframe.html",
+                                       "ipAddRessOrigin_worker.js");
+
+    var worker = new Worker(url);
+    worker.onmessage = function (event) {
+      window.parent.postMessage(event.data, "*");
+    };
+  }
+
+</script>
+</body>
+</html>
diff --git a/dom/workers/test/ipAddressOrigin_worker.js b/dom/workers/test/ipAddressOrigin_worker.js
new file mode 100644
index 000000000000..92ef04503976
--- /dev/null
+++ b/dom/workers/test/ipAddressOrigin_worker.js
@@ -0,0 +1,5 @@
+/**
+* Any copyright is dedicated to the Public Domain.
+* http://creativecommons.org/publicdomain/zero/1.0/
+*/
+postMessage("done");
diff --git a/dom/workers/test/test_ipAddressOrigin.html b/dom/workers/test/test_ipAddressOrigin.html
new file mode 100644
index 000000000000..1f48e1b68fdb
--- /dev/null
+++ b/dom/workers/test/test_ipAddressOrigin.html
@@ -0,0 +1,42 @@
+<!--
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test for Web Workers</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body onload="go();">
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<iframe id="testFrame"></iframe>
+<script class="testbody" type="text/javascript">
+
+  function go() {
+    var iframe = document.getElementById("testFrame");
+
+    iframe.addEventListener("load", function() {
+      iframe.contentWindow.postMessage("go", "*");
+      window.addEventListener("message", function(event) {
+        is(event.data, "done", "Correct message");
+        SimpleTest.finish();
+      }, "false");
+    }, false);
+
+    iframe.src =
+      "http://127.0.0.1" +
+      window.location.pathname.replace("test_ipAddressOrigin.html",
+                                       "ipAddressOrigin_iframe.html");
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/netwerk/base/public/mozIThirdPartyUtil.idl b/netwerk/base/public/mozIThirdPartyUtil.idl
index e0b40ef29c30..ad419857692e 100644
--- a/netwerk/base/public/mozIThirdPartyUtil.idl
+++ b/netwerk/base/public/mozIThirdPartyUtil.idl
@@ -45,7 +45,7 @@ interface nsIChannel;
  * Utility functions for determining whether a given URI, channel, or window
  * hierarchy is third party with respect to a known URI.
  */
-[scriptable, uuid(55385caa-1b94-4376-a34c-b47c51ef0837)]
+[scriptable, uuid(d994fd1d-d2fe-4372-9ae7-88b08b7d9d90)]
 interface mozIThirdPartyUtil : nsISupports
 {
   /**
@@ -155,6 +155,24 @@ interface mozIThirdPartyUtil : nsISupports
    * @see isThirdPartyWindow
    */
   boolean isThirdPartyChannel(in nsIChannel aChannel, [optional] in nsIURI aURI);
+
+  /**
+   * getBaseDomain
+   *
+   * Get the base domain for aHostURI; e.g. for "www.bbc.co.uk", this would be
+   * "bbc.co.uk". Only properly-formed URI's are tolerated, though a trailing
+   * dot may be present. If aHostURI is an IP address, an alias such as
+   * 'localhost', an eTLD such as 'co.uk', or the empty string, aBaseDomain will
+   * be the exact host. The result of this function should only be used in exact
+   * string comparisons, since substring comparisons will not be valid for the
+   * special cases elided above.
+   *
+   * @param aHostURI
+   *        The URI to analyze.
+   *
+   * @return the base domain.
+   */
+  AUTF8String getBaseDomain(in nsIURI aHostURI);
 };
 
 %{ C++