diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index 5d1b555df987..ec08b205c314 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -45,6 +45,7 @@ use gfx_traits::Epoch;
 use heapsize::HeapSizeOf;
 use hyper::header::Headers;
 use hyper::method::Method;
+use ipc_channel::{Error as IpcError};
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use libc::c_void;
 use msg::constellation_msg::{BrowsingContextId, TopLevelBrowsingContextId, FrameType, Key, KeyModifiers, KeyState};
@@ -500,7 +501,7 @@ pub struct InitialScriptState {
     /// A port on which messages sent by the constellation to script can be received.
     pub control_port: IpcReceiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
-    pub constellation_chan: IpcSender<ScriptMsg>,
+    pub script_to_constellation_chan: ScriptToConstellationChan,
     /// A sender for the layout thread to communicate to the constellation.
     pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
     /// A channel to schedule timer events.
@@ -780,7 +781,7 @@ pub struct WorkerGlobalScopeInit {
     /// From devtools sender
     pub from_devtools_sender: Option<IpcSender<DevtoolScriptControlMsg>>,
     /// Messages to send to constellation
-    pub constellation_chan: IpcSender<ScriptMsg>,
+    pub script_to_constellation_chan: ScriptToConstellationChan,
     /// Message to send to the scheduler
     pub scheduler_chan: IpcSender<TimerSchedulerMsg>,
     /// The worker id
@@ -843,3 +844,19 @@ pub struct DrawAPaintImageResult {
     /// Drawing the image might have requested loading some image URLs.
     pub missing_image_urls: Vec<ServoUrl>,
 }
+
+/// A Script to Constellation channel.
+#[derive(Deserialize, Serialize, Clone)]
+pub struct ScriptToConstellationChan {
+    /// Sender for communicating with constellation thread.
+    pub sender: IpcSender<(PipelineId, ScriptMsg)>,
+    /// Used to identify the origin of the message.
+    pub pipeline_id: PipelineId,
+}
+
+impl ScriptToConstellationChan {
+    /// Send ScriptMsg and attach the pipeline_id to the message.
+    pub fn send(&self, msg: ScriptMsg) -> Result<(), IpcError> {
+        self.sender.send((self.pipeline_id, msg))
+    }
+}