--- a/widget/gonk/nativewindow/FakeSurfaceComposer.cpp
+++ b/widget/gonk/nativewindow/FakeSurfaceComposer.cpp
@@ -477,55 +477,56 @@ FakeSurfaceComposer::captureScreenImp(co
                 reqWidth, reqHeight, hw_w, hw_h);
         static_cast<GraphicProducerWrapper*>(producer->asBinder().get())->exit(BAD_VALUE);
         return;
     }
 
     reqWidth  = (!reqWidth)  ? hw_w : reqWidth;
     reqHeight = (!reqHeight) ? hw_h : reqHeight;
 
-    nsScreenGonk* screenPtr = screen.forget().take();
     nsCOMPtr<nsIRunnable> runnable =
-        NS_NewRunnableFunction([screenPtr, reqWidth, reqHeight, producer, wrapper]() {
+        NS_NewRunnableFunction([screen, reqWidth, reqHeight, producer, wrapper]() {
             // create a surface (because we're a producer, and we need to
             // dequeue/queue a buffer)
             sp<Surface> sur = new Surface(producer);
             ANativeWindow* window = sur.get();
+            // The closure makes screen const and we can't call forget() on it.
+            RefPtr<nsScreenGonk> screenAlias = screen;
 
             if (native_window_api_connect(window, NATIVE_WINDOW_API_EGL) != NO_ERROR) {
                 static_cast<GraphicProducerWrapper*>(producer->asBinder().get())->exit(BAD_VALUE);
-                NS_ReleaseOnMainThread(screenPtr);
+                NS_ReleaseOnMainThread(screenAlias.forget());
                 return;
             }
             uint32_t usage = GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_SW_WRITE_OFTEN |
                              GRALLOC_USAGE_HW_RENDER | GRALLOC_USAGE_HW_TEXTURE;
 
             int err = 0;
             err = native_window_set_buffers_dimensions(window, reqWidth, reqHeight);
             err |= native_window_set_scaling_mode(window, NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW);
             err |= native_window_set_buffers_format(window, HAL_PIXEL_FORMAT_RGBA_8888);
             err |= native_window_set_usage(window, usage);
 
             status_t result = NO_ERROR;
             if (err == NO_ERROR) {
                 ANativeWindowBuffer* buffer;
                 result = native_window_dequeue_buffer_and_wait(window,  &buffer);
                 if (result == NO_ERROR) {
-                    nsresult rv = screenPtr->MakeSnapshot(buffer);
+                    nsresult rv = screen->MakeSnapshot(buffer);
                     if (rv != NS_OK) {
                         result = INVALID_OPERATION;
                     }
                     window->queueBuffer(window, buffer, -1);
                 }
             } else {
                 result = BAD_VALUE;
             }
             native_window_api_disconnect(window, NATIVE_WINDOW_API_EGL);
             static_cast<GraphicProducerWrapper*>(producer->asBinder().get())->exit(result);
-            NS_ReleaseOnMainThread(screenPtr);
+            NS_ReleaseOnMainThread(screenAlias.forget());
         });
 
     mozilla::layers::CompositorParent::CompositorLoop()->PostTask(
         FROM_HERE, new RunnableCallTask(runnable));
 }
 
 #if ANDROID_VERSION >= 21
 void