diff --git a/caps/BasePrincipal.cpp b/caps/BasePrincipal.cpp
index ae328a8de84b..93a39fbfd544 100644
--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -115,6 +115,12 @@ OriginAttributes::PopulateFromSuffix(const nsACString& aStr)
   return usp->ForEach(iterator);
 }
 
+void
+OriginAttributes::CookieJar(nsACString& aStr)
+{
+  mozilla::GetJarPrefix(mAppId, mInBrowser, aStr);
+}
+
 BasePrincipal::BasePrincipal()
 {}
 
@@ -223,7 +229,7 @@ BasePrincipal::GetJarPrefix(nsACString& aJarPrefix)
 {
   MOZ_ASSERT(AppId() != nsIScriptSecurityManager::UNKNOWN_APP_ID);
 
-  mozilla::GetJarPrefix(AppId(), IsInBrowserElement(), aJarPrefix);
+  mOriginAttributes.CookieJar(aJarPrefix);
   return NS_OK;
 }
 
@@ -246,10 +252,8 @@ BasePrincipal::GetOriginSuffix(nsACString& aOriginAttributes)
 NS_IMETHODIMP
 BasePrincipal::GetCookieJar(nsACString& aCookieJar)
 {
-  // We just forward to .jarPrefix for now, which is a nice compact
-  // stringification of the (appId, inBrowser) tuple. This will eventaully be
-  // swapped out for an origin attribute - see the comment in nsIPrincipal.idl.
-  return GetJarPrefix(aCookieJar);
+  mOriginAttributes.CookieJar(aCookieJar);
+  return NS_OK;
 }
 
 NS_IMETHODIMP
diff --git a/caps/BasePrincipal.h b/caps/BasePrincipal.h
index 377869b55264..feb4aa9db127 100644
--- a/caps/BasePrincipal.h
+++ b/caps/BasePrincipal.h
@@ -28,6 +28,8 @@ public:
     mAppId = aAppId;
     mInBrowser = aInBrowser;
   }
+  explicit OriginAttributes(const OriginAttributesDictionary& aOther)
+    : OriginAttributesDictionary(aOther) {}
 
   bool operator==(const OriginAttributes& aOther) const
   {
@@ -44,6 +46,8 @@ public:
   // returns an empty string.
   void CreateSuffix(nsACString& aStr) const;
   bool PopulateFromSuffix(const nsACString& aStr);
+
+  void CookieJar(nsACString& aStr);
 };
 
 /*
diff --git a/dom/webidl/ChromeUtils.webidl b/dom/webidl/ChromeUtils.webidl
index 11683eb76a74..64cab34a1555 100644
--- a/dom/webidl/ChromeUtils.webidl
+++ b/dom/webidl/ChromeUtils.webidl
@@ -28,6 +28,15 @@ interface ChromeUtils {
    */
   [Throws, NewObject]
   static HeapSnapshot readHeapSnapshot(DOMString filePath);
+
+  /**
+   * A helper that converts OriginAttributesDictionary to cookie jar opaque
+   * identfier.
+   *
+   * @param originAttrs       The originAttributes from the caller.
+   */
+  static ByteString
+  originAttributesToCookieJar(optional OriginAttributesDictionary originAttrs);
 };
 
 /**
diff --git a/toolkit/devtools/server/ChromeUtils.cpp b/toolkit/devtools/server/ChromeUtils.cpp
index 4e5968356422..b2eb58c9c0f0 100644
--- a/toolkit/devtools/server/ChromeUtils.cpp
+++ b/toolkit/devtools/server/ChromeUtils.cpp
@@ -11,6 +11,7 @@
 #include "mozilla/devtools/HeapSnapshot.h"
 #include "mozilla/devtools/ZeroCopyNSIOutputStream.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/BasePrincipal.h"
 #include "mozilla/UniquePtr.h"
 
 #include "nsCRTGlue.h"
@@ -428,5 +429,14 @@ ChromeUtils::ReadHeapSnapshot(GlobalObject& global,
   return HeapSnapshot::Create(cx, global, buffer.get(), size, rv);
 }
 
+/* static */ void
+ChromeUtils::OriginAttributesToCookieJar(GlobalObject& aGlobal,
+                                         const OriginAttributesDictionary& aAttrs,
+                                         nsCString& aCookieJar)
+{
+  OriginAttributes attrs(aAttrs);
+  attrs.CookieJar(aCookieJar);
+}
+
 } // namespace devtools
 } // namespace mozilla
diff --git a/toolkit/devtools/server/ChromeUtils.h b/toolkit/devtools/server/ChromeUtils.h
index 047194b3d3d3..ef4e2180bc92 100644
--- a/toolkit/devtools/server/ChromeUtils.h
+++ b/toolkit/devtools/server/ChromeUtils.h
@@ -73,6 +73,11 @@ public:
                                                          JSContext* cx,
                                                          const nsAString& filePath,
                                                          ErrorResult& rv);
+
+  static void
+  OriginAttributesToCookieJar(dom::GlobalObject& aGlobal,
+                              const dom::OriginAttributesDictionary& aAttrs,
+                              nsCString& aCookieJar);
 };
 
 } // namespace devtools
diff --git a/toolkit/devtools/server/tests/unit/test_originAttributesToCookieJar.js b/toolkit/devtools/server/tests/unit/test_originAttributesToCookieJar.js
new file mode 100644
index 000000000000..e46057075906
--- /dev/null
+++ b/toolkit/devtools/server/tests/unit/test_originAttributesToCookieJar.js
@@ -0,0 +1,26 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+Cu.import("resource://gre/modules/Services.jsm");
+var ssm = Services.scriptSecurityManager;
+
+function run_test() {
+  const appId = 12;
+  var browserAttrs = {appId: appId, inBrowser: true};
+
+  // ChromeUtils.originAttributesToCookieJar should return the same value with
+  // the cookieJar of the principal created from the same origin attribute.
+  var cookieJar_1 = ChromeUtils.originAttributesToCookieJar(browserAttrs);
+  var dummy = Services.io.newURI("http://example.com", null, null);
+  var cookieJar_2 = ssm.createCodebasePrincipal(dummy, browserAttrs).cookieJar;
+  do_check_eq(cookieJar_1, cookieJar_2);
+
+  // App and mozbrowser shouldn't have the same cookieJar identifier.
+  var appAttrs = {appId: appId, inBrowser: false};
+  var cookieJar_3 = ChromeUtils.originAttributesToCookieJar(appAttrs);
+  do_check_neq(cookieJar_1, cookieJar_3);
+
+  // If the attribute is null the cookieJar identifier should be empty.
+  var cookieJar_4 = ChromeUtils.originAttributesToCookieJar();
+  do_check_eq(cookieJar_4, "");
+}
diff --git a/toolkit/devtools/server/tests/unit/xpcshell.ini b/toolkit/devtools/server/tests/unit/xpcshell.ini
index 9e92fa92c5da..2bb264090192 100644
--- a/toolkit/devtools/server/tests/unit/xpcshell.ini
+++ b/toolkit/devtools/server/tests/unit/xpcshell.ini
@@ -80,6 +80,7 @@ support-files =
 [test_eval-03.js]
 [test_eval-04.js]
 [test_eval-05.js]
+[test_originAttributesToCookieJar.js]
 [test_promises_actor_attach.js]
 [test_promises_actor_exist.js]
 [test_promises_actor_list_promises.js]