diff --git a/js/src/xpconnect/idl/xpccomponents.idl b/js/src/xpconnect/idl/xpccomponents.idl
index 2e0ad7b2a0a..4869985dbf0 100644
--- a/js/src/xpconnect/idl/xpccomponents.idl
+++ b/js/src/xpconnect/idl/xpccomponents.idl
@@ -120,10 +120,19 @@ interface nsIXPCComponents_utils_Sandbox : nsISupports
 {
 };
 
+/**
+ * interface for callback to be passed to Cu.schedulePreciseGC
+ */
+[scriptable, function, uuid(71000535-b0fd-44d1-8ce0-909760e3953c)]
+interface ScheduledGCCallback : nsISupports
+{
+    void callback();
+};
+
 /**
 * interface of Components.utils
 */
-[scriptable, uuid(5f0acf45-135a-48d1-976c-082ce3b24ead)]
+[scriptable, uuid(fed2d752-6cb3-4135-97b0-2c290e541e2d)]
 interface nsIXPCComponents_Utils : nsISupports
 {
 
@@ -228,6 +237,13 @@ interface nsIXPCComponents_Utils : nsISupports
      */
     void forceGC();
 
+    /*
+     * Schedule a garbage collection cycle for a point in the future when no JS
+     * is running. Call the provided function once this has occurred.
+     */
+    [implicit_jscontext]
+    void schedulePreciseGC(in ScheduledGCCallback callback);
+
     /*
      * To be called from JS only.
      *
diff --git a/js/src/xpconnect/src/xpccomponents.cpp b/js/src/xpconnect/src/xpccomponents.cpp
index 0e8cb62b95a..de2248e3ca1 100644
--- a/js/src/xpconnect/src/xpccomponents.cpp
+++ b/js/src/xpconnect/src/xpccomponents.cpp
@@ -55,6 +55,7 @@
 #include "nsNullPrincipal.h"
 #include "nsJSUtils.h"
 #include "mozJSComponentLoader.h"
+#include "nsContentUtils.h"
 
 /***************************************************************************/
 // stuff used by all
@@ -3775,6 +3776,48 @@ nsXPCComponents_Utils::ForceGC()
     return NS_OK;
 }
 
+class PreciseGCRunnable : public nsRunnable
+{
+  public:
+    PreciseGCRunnable(JSContext *aCx, ScheduledGCCallback* aCallback)
+    : mCallback(aCallback), mCx(aCx) {}
+
+    NS_IMETHOD Run()
+    {
+        nsCOMPtr<nsIJSRuntimeService> runtimeSvc = do_GetService("@mozilla.org/js/xpc/RuntimeService;1");
+        NS_ENSURE_STATE(runtimeSvc);
+
+        JSRuntime* rt = nsnull;
+        runtimeSvc->GetRuntime(&rt);
+        NS_ENSURE_STATE(rt);
+
+        JSContext *cx;
+        JSContext *iter = nsnull;
+        while ((cx = JS_ContextIterator(rt, &iter)) != NULL) {
+            if (JS_IsRunning(cx)) {
+                return NS_DispatchToMainThread(this);
+            }
+        }
+
+        JS_GC(mCx);
+
+        mCallback->Callback();
+        return NS_OK;
+    }
+
+  private:
+    nsRefPtr<ScheduledGCCallback> mCallback;
+    JSContext *mCx;
+};
+
+/* [inline_jscontext] void schedulePreciseGC(in ScheduledGCCallback callback); */
+NS_IMETHODIMP
+nsXPCComponents_Utils::SchedulePreciseGC(ScheduledGCCallback* aCallback, JSContext* aCx)
+{
+    nsRefPtr<PreciseGCRunnable> event = new PreciseGCRunnable(aCx, aCallback);
+    return NS_DispatchToMainThread(event);
+}
+
 /* void getGlobalForObject(); */
 NS_IMETHODIMP
 nsXPCComponents_Utils::GetGlobalForObject()
diff --git a/js/src/xpconnect/tests/chrome/Makefile.in b/js/src/xpconnect/tests/chrome/Makefile.in
index 020dd6063f6..ac80ca682d8 100644
--- a/js/src/xpconnect/tests/chrome/Makefile.in
+++ b/js/src/xpconnect/tests/chrome/Makefile.in
@@ -66,6 +66,7 @@ _CHROME_FILES = \
 		test_bug596580.xul \
 		test_bug654370.xul \
 		test_bug658560.xul \
+                test_precisegc.xul \
 		$(NULL)
 
 # Disabled until this test gets updated to test the new proxy based
diff --git a/js/src/xpconnect/tests/chrome/test_precisegc.xul b/js/src/xpconnect/tests/chrome/test_precisegc.xul
new file mode 100644
index 00000000000..aa956a42106
--- /dev/null
+++ b/js/src/xpconnect/tests/chrome/test_precisegc.xul
@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 661927"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script type="application/javascript"
+          src="chrome://mochikit/content/MochiKit/packed.js"></script>
+  <script type="application/javascript"
+          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      Components.utils.schedulePreciseGC(
+        function() {
+          ok(true, "callback executed");
+          SimpleTest.finish();
+        });
+      SimpleTest.waitForExplicitFinish();
+  ]]></script>
+</window>