diff --git a/servo/components/compositing/Cargo.toml b/servo/components/compositing/Cargo.toml
index 95ddbc9cfc78..ce452ad8b7d1 100644
--- a/servo/components/compositing/Cargo.toml
+++ b/servo/components/compositing/Cargo.toml
@@ -68,14 +68,20 @@ features = ["texture_surface"]
 version = "0.2"
 features = [ "serde_serialization" ]
 
+[dependencies.gaol]
+git = "https://github.com/pcwalton/gaol"
+
 [dependencies]
 app_units = {version = "0.1", features = ["plugins"]}
 image = "0.4.0"
+libc = "0.1"
 log = "0.3"
 num = "0.1.24"
 time = "0.1.17"
 gleam = "0.1"
 euclid = {version = "0.3", features = ["plugins"]}
+serde = "0.6"
+serde_macros = "0.6"
 
 [target.x86_64-apple-darwin.dependencies]
 core-graphics = "0.1"
diff --git a/servo/components/compositing/compositor.rs b/servo/components/compositing/compositor.rs
index c251426dc489..e91bc9510866 100644
--- a/servo/components/compositing/compositor.rs
+++ b/servo/components/compositing/compositor.rs
@@ -17,7 +17,7 @@ use gfx_traits::color;
 use gleam::gl;
 use gleam::gl::types::{GLint, GLsizei};
 use image::{DynamicImage, ImageFormat, RgbImage};
-use ipc_channel::ipc::{self, IpcSharedMemory};
+use ipc_channel::ipc::{self, IpcSender, IpcSharedMemory};
 use ipc_channel::router::ROUTER;
 use layers::geometry::{DevicePixel, LayerPixel};
 use layers::layers::{BufferRequest, Layer, LayerBuffer, LayerBufferSet};
@@ -30,7 +30,7 @@ use msg::compositor_msg::{Epoch, EventResult, FrameTreeId, LayerId, LayerKind};
 use msg::compositor_msg::{LayerProperties, ScrollPolicy};
 use msg::constellation_msg::CompositorMsg as ConstellationMsg;
 use msg::constellation_msg::{AnimationState, Image, PixelFormat};
-use msg::constellation_msg::{ConstellationChan, Key, KeyModifiers, KeyState, LoadData};
+use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{NavigationDirection, PipelineId, WindowSizeData};
 use pipeline::CompositionPipeline;
 use profile_traits::mem::{self, ReportKind, Reporter, ReporterRequest};
@@ -168,7 +168,7 @@ pub struct IOCompositor<Window: WindowMethods> {
     frame_tree_id: FrameTreeId,
 
     /// The channel on which messages can be sent to the constellation.
-    constellation_chan: ConstellationChan<ConstellationMsg>,
+    constellation_chan: Sender<ConstellationMsg>,
 
     /// The channel on which messages can be sent to the time profiler.
     time_profiler_chan: time::ProfilerChan,
@@ -385,8 +385,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
     pub fn start_shutting_down(&mut self) {
         debug!("Compositor sending Exit message to Constellation");
-        let ConstellationChan(ref constellation_channel) = self.constellation_chan;
-        constellation_channel.send(ConstellationMsg::Exit).unwrap();
+        self.constellation_chan.send(ConstellationMsg::Exit).unwrap();
 
         self.mem_profiler_chan.send(mem::ProfilerMsg::UnregisterReporter(reporter_name()));
 
@@ -702,8 +701,8 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
     fn set_frame_tree(&mut self,
                       frame_tree: &SendableFrameTree,
-                      response_chan: Sender<()>,
-                      new_constellation_chan: ConstellationChan<ConstellationMsg>) {
+                      response_chan: IpcSender<()>,
+                      new_constellation_chan: Sender<ConstellationMsg>) {
         response_chan.send(()).unwrap();
 
         // There are now no more pending iframes.
@@ -943,8 +942,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         let initial_viewport = self.window_size.as_f32() / dppx;
         let visible_viewport = initial_viewport / self.viewport_zoom;
 
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(ConstellationMsg::ResizedWindow(WindowSizeData {
+        self.constellation_chan.send(ConstellationMsg::ResizedWindow(WindowSizeData {
             device_pixel_ratio: dppx,
             initial_viewport: initial_viewport,
             visible_viewport: visible_viewport,
@@ -959,9 +957,9 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             None => return,
         };
 
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(ConstellationMsg::FrameSize(*subpage_pipeline_id,
-                                              layer_properties.rect.size)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::FrameSize(
+            *subpage_pipeline_id,
+            layer_properties.rect.size)).unwrap();
     }
 
     pub fn move_layer(&self,
@@ -1168,8 +1166,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             None => ConstellationMsg::InitLoadUrl(url)
         };
 
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(msg).unwrap()
+        self.constellation_chan.send(msg).unwrap()
     }
 
     fn on_mouse_window_event_class(&mut self, mouse_window_event: MouseWindowEvent) {
@@ -1446,7 +1443,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
     }
 
     fn tick_animations_for_pipeline(&self, pipeline_id: PipelineId) {
-        self.constellation_chan.0.send(ConstellationMsg::TickAnimation(pipeline_id)).unwrap()
+        self.constellation_chan.send(ConstellationMsg::TickAnimation(pipeline_id)).unwrap()
     }
 
     fn constrain_viewport(&mut self, pipeline_id: PipelineId, constraints: ViewportConstraints) {
@@ -1538,13 +1535,11 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             windowing::WindowNavigateMsg::Forward => NavigationDirection::Forward,
             windowing::WindowNavigateMsg::Back => NavigationDirection::Back,
         };
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(ConstellationMsg::Navigate(None, direction)).unwrap()
+        self.constellation_chan.send(ConstellationMsg::Navigate(None, direction)).unwrap()
     }
 
     fn on_key_event(&self, key: Key, state: KeyState, modifiers: KeyModifiers) {
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(ConstellationMsg::KeyEvent(key, state, modifiers)).unwrap()
+        self.constellation_chan.send(ConstellationMsg::KeyEvent(key, state, modifiers)).unwrap()
     }
 
     fn fill_paint_request_with_cached_layer_buffers(&mut self, paint_request: &mut PaintRequest) {
@@ -1744,8 +1739,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
                 // Pass the pipeline/epoch states to the constellation and check
                 // if it's safe to output the image.
-                let ConstellationChan(ref chan) = self.constellation_chan;
-                chan.send(ConstellationMsg::IsReadyToSaveImage(pipeline_epochs)).unwrap();
+                self.constellation_chan.send(ConstellationMsg::IsReadyToSaveImage(pipeline_epochs)).unwrap();
                 self.ready_to_save_state = ReadyState::WaitingForConstellationReply;
                 Err(NotReadyToPaint::JustNotifiedConstellation)
             }
@@ -2167,8 +2161,7 @@ impl<Window> CompositorEventListener for IOCompositor<Window> where Window: Wind
             None => return,
             Some(ref root_pipeline) => root_pipeline.id,
         };
-        let ConstellationChan(ref chan) = self.constellation_chan;
-        chan.send(ConstellationMsg::GetPipelineTitle(root_pipeline_id)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::GetPipelineTitle(root_pipeline_id)).unwrap();
     }
 }
 
diff --git a/servo/components/compositing/compositor_task.rs b/servo/components/compositing/compositor_task.rs
index 70c59132b6d3..9e5c59d54679 100644
--- a/servo/components/compositing/compositor_task.rs
+++ b/servo/components/compositing/compositor_task.rs
@@ -5,15 +5,16 @@
 //! Communication with the compositor task.
 
 use compositor;
-use euclid::{Point2D, Size2D};
+use euclid::point::Point2D;
+use euclid::size::Size2D;
 use headless;
-use ipc_channel::ipc::{IpcReceiver, IpcSender};
+use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use layers::layers::{BufferRequest, LayerBufferSet};
 use layers::platform::surface::{NativeDisplay, NativeSurface};
 use msg::compositor_msg::{Epoch, EventResult, FrameTreeId, LayerId, LayerProperties};
 use msg::compositor_msg::{PaintListener, ScriptToCompositorMsg};
 use msg::constellation_msg::CompositorMsg as ConstellationMsg;
-use msg::constellation_msg::{AnimationState, ConstellationChan, PipelineId};
+use msg::constellation_msg::{AnimationState, PipelineId};
 use msg::constellation_msg::{Image, Key, KeyModifiers, KeyState};
 use profile_traits::mem;
 use profile_traits::time;
@@ -60,11 +61,11 @@ pub fn run_script_listener_thread(compositor_proxy: Box<CompositorProxy + 'stati
                                   receiver: IpcReceiver<ScriptToCompositorMsg>) {
     while let Ok(msg) = receiver.recv() {
         match msg {
-            ScriptToCompositorMsg::ScrollFragmentPoint(pipeline_id, layer_id, point, _smooth) => {
+            ScriptToCompositorMsg::ScrollFragmentPoint(pipeline_id, layer_id, point, smooth) => {
                 compositor_proxy.send(Msg::ScrollFragmentPoint(pipeline_id,
                                                                layer_id,
                                                                point,
-                                                               _smooth));
+                                                               smooth));
             }
 
             ScriptToCompositorMsg::GetClientWindow(send) => {
@@ -80,7 +81,7 @@ pub fn run_script_listener_thread(compositor_proxy: Box<CompositorProxy + 'stati
             }
 
             ScriptToCompositorMsg::Exit => {
-                let (chan, port) = channel();
+                let (chan, port) = ipc::channel().unwrap();
                 compositor_proxy.send(Msg::Exit(chan));
                 port.recv().unwrap();
             }
@@ -152,7 +153,7 @@ impl PaintListener for Box<CompositorProxy + 'static + Send> {
 /// Messages from the painting task and the constellation task to the compositor task.
 pub enum Msg {
     /// Requests that the compositor shut down.
-    Exit(Sender<()>),
+    Exit(IpcSender<()>),
 
     /// Informs the compositor that the constellation has completed shutdown.
     /// Required because the constellation can have pending calls to make
@@ -180,7 +181,7 @@ pub enum Msg {
     /// Alerts the compositor that the given pipeline has changed whether it is running animations.
     ChangeRunningAnimationsState(PipelineId, AnimationState),
     /// Replaces the current frame tree, typically called during main frame navigation.
-    SetFrameTree(SendableFrameTree, Sender<()>, ConstellationChan<ConstellationMsg>),
+    SetFrameTree(SendableFrameTree, IpcSender<()>, Sender<ConstellationMsg>),
     /// The load of a page has begun: (can go back, can go forward).
     LoadStart(bool, bool),
     /// The load of a page has completed: (can go back, can go forward).
@@ -296,7 +297,7 @@ pub struct InitialCompositorState {
     /// A port on which messages inbound to the compositor can be received.
     pub receiver: Box<CompositorReceiver>,
     /// A channel to the constellation.
-    pub constellation_chan: ConstellationChan<ConstellationMsg>,
+    pub constellation_chan: Sender<ConstellationMsg>,
     /// A channel to the time profiler thread.
     pub time_profiler_chan: time::ProfilerChan,
     /// A channel to the memory profiler thread.
diff --git a/servo/components/compositing/constellation.rs b/servo/components/compositing/constellation.rs
index 8d8d24d050ad..2084ace97014 100644
--- a/servo/components/compositing/constellation.rs
+++ b/servo/components/compositing/constellation.rs
@@ -18,8 +18,11 @@ use compositor_task::Msg as ToCompositorMsg;
 use devtools_traits::{ChromeToDevtoolsControlMsg, DevtoolsControlMsg};
 use euclid::scale_factor::ScaleFactor;
 use euclid::size::{Size2D, TypedSize2D};
+use gaol;
+use gaol::sandbox::{self, Sandbox, SandboxMethods};
 use gfx::font_cache_task::FontCacheTask;
-use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::ipc::{self, IpcOneShotServer, IpcSender};
+use ipc_channel::router::ROUTER;
 use layout_traits::{LayoutControlChan, LayoutTaskFactory};
 use msg::compositor_msg::Epoch;
 use msg::constellation_msg::AnimationState;
@@ -37,19 +40,21 @@ use net_traits::image_cache_task::ImageCacheTask;
 use net_traits::storage_task::{StorageTask, StorageTaskMsg};
 use net_traits::{self, ResourceTask};
 use offscreen_gl_context::GLContextAttributes;
-use pipeline::{CompositionPipeline, InitialPipelineState, Pipeline};
+use pipeline::{CompositionPipeline, InitialPipelineState, Pipeline, UnprivilegedPipelineContent};
 use profile_traits::mem;
 use profile_traits::time;
+use sandboxing;
 use script_traits::{CompositorEvent, ConstellationControlMsg, LayoutControlMsg};
 use script_traits::{ScriptState, ScriptTaskFactory};
 use script_traits::{TimerEventRequest};
 use std::borrow::ToOwned;
 use std::collections::HashMap;
+use std::env;
 use std::io::{self, Write};
 use std::marker::PhantomData;
 use std::mem::replace;
 use std::process;
-use std::sync::mpsc::{Receiver, Sender, channel};
+use std::sync::mpsc::{Sender, channel, Receiver};
 use style_traits::viewport::ViewportConstraints;
 use timer_scheduler::TimerScheduler;
 use url::Url;
@@ -79,7 +84,7 @@ pub struct Constellation<LTF, STF> {
     pub script_sender: ConstellationChan<FromScriptMsg>,
 
     /// A channel through which compositor messages can be sent to this object.
-    pub compositor_sender: ConstellationChan<FromCompositorMsg>,
+    pub compositor_sender: Sender<FromCompositorMsg>,
 
     /// Receives messages from scripts.
     pub script_receiver: Receiver<FromScriptMsg>,
@@ -156,6 +161,9 @@ pub struct Constellation<LTF, STF> {
     webgl_paint_tasks: Vec<Sender<CanvasMsg>>,
 
     scheduler_chan: IpcSender<TimerEventRequest>,
+
+    /// A list of child content processes.
+    child_processes: Vec<ChildProcess>,
 }
 
 /// State needed to construct a constellation.
@@ -259,14 +267,21 @@ enum ExitPipelineMode {
     Force,
 }
 
+enum ChildProcess {
+    Sandboxed(gaol::platform::process::Process),
+    Unsandboxed(process::Child),
+}
+
 impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
-    pub fn start(state: InitialConstellationState) -> ConstellationChan<FromCompositorMsg> {
-        let (script_receiver, script_sender) = ConstellationChan::<FromScriptMsg>::new();
-        let (compositor_receiver, compositor_sender) = ConstellationChan::<FromCompositorMsg>::new();
+    pub fn start(state: InitialConstellationState) -> Sender<FromCompositorMsg> {
+        let (ipc_script_receiver, ipc_script_sender) = ConstellationChan::<FromScriptMsg>::new();
+        //let (script_receiver, script_sender) = channel();
+        let script_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_script_receiver);
+        let (compositor_sender, compositor_receiver) = channel();
         let compositor_sender_clone = compositor_sender.clone();
         spawn_named("Constellation".to_owned(), move || {
             let mut constellation: Constellation<LTF, STF> = Constellation {
-                script_sender: script_sender,
+                script_sender: ipc_script_sender,
                 compositor_sender: compositor_sender_clone,
                 script_receiver: script_receiver,
                 compositor_receiver: compositor_receiver,
@@ -305,6 +320,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 canvas_paint_tasks: Vec::new(),
                 webgl_paint_tasks: Vec::new(),
                 scheduler_chan: TimerScheduler::start(),
+                child_processes: Vec::new(),
             };
             let namespace_id = constellation.next_pipeline_namespace_id();
             PipelineNamespace::install(namespace_id);
@@ -333,10 +349,10 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                     pipeline_id: PipelineId,
                     parent_info: Option<(PipelineId, SubpageId)>,
                     initial_window_size: Option<TypedSize2D<PagePx, f32>>,
-                    script_channel: Option<Sender<ConstellationControlMsg>>,
+                    script_channel: Option<IpcSender<ConstellationControlMsg>>,
                     load_data: LoadData) {
         let spawning_paint_only = script_channel.is_some();
-        let (pipeline, mut pipeline_content) =
+        let (pipeline, unprivileged_pipeline_content, mut privileged_pipeline_content) =
             Pipeline::create::<LTF, STF>(InitialPipelineState {
                 id: pipeline_id,
                 parent_info: parent_info,
@@ -357,12 +373,39 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 pipeline_namespace_id: self.next_pipeline_namespace_id(),
             });
 
-        // TODO(pcwalton): In multiprocess mode, send that `PipelineContent` instance over to
-        // the content process and call this over there.
         if spawning_paint_only {
-            pipeline_content.start_paint_task();
+            privileged_pipeline_content.start_paint_task();
         } else {
-            pipeline_content.start_all::<LTF, STF>();
+            privileged_pipeline_content.start_all();
+
+            // Spawn the child process.
+            //
+            // Yes, that's all there is to it!
+            if opts::multiprocess() {
+                let (server, token) =
+                    IpcOneShotServer::<IpcSender<UnprivilegedPipelineContent>>::new().unwrap();
+
+                // If there is a sandbox, use the `gaol` API to create the child process.
+                let child_process = if opts::get().sandbox {
+                    let mut command = sandbox::Command::me().unwrap();
+                    command.arg("--content-process").arg(token);
+                    let profile = sandboxing::content_process_sandbox_profile();
+                    ChildProcess::Sandboxed(Sandbox::new(profile).start(&mut command).expect(
+                        "Failed to start sandboxed child process!"))
+                } else {
+                    let path_to_self = env::current_exe().unwrap();
+                    let mut child_process = process::Command::new(path_to_self);
+                    child_process.arg("--content-process");
+                    child_process.arg(token);
+                    ChildProcess::Unsandboxed(child_process.spawn().unwrap())
+                };
+                self.child_processes.push(child_process);
+
+                let (_receiver, sender) = server.accept().unwrap();
+                sender.send(unprivileged_pipeline_content).unwrap();
+            } else {
+                unprivileged_pipeline_content.start_all::<LTF, STF>(false);
+            }
         }
 
         assert!(!self.pipelines.contains_key(&pipeline_id));
@@ -1290,7 +1333,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
 
             // Synchronously query the script task for this pipeline
             // to see if it is idle.
-            let (sender, receiver) = channel();
+            let (sender, receiver) = ipc::channel().unwrap();
             let msg = ConstellationControlMsg::GetCurrentState(sender, frame.current);
             pipeline.script_chan.send(msg).unwrap();
             let result = receiver.recv().unwrap();
@@ -1445,7 +1488,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
         if let Some(root_frame_id) = self.root_frame_id {
             let frame_tree = self.frame_to_sendable(root_frame_id);
 
-            let (chan, port) = channel();
+            let (chan, port) = ipc::channel().unwrap();
             self.compositor_proxy.send(ToCompositorMsg::SetFrameTree(frame_tree,
                                                                    chan,
                                                                    self.compositor_sender.clone()));
diff --git a/servo/components/compositing/headless.rs b/servo/components/compositing/headless.rs
index 52435af0cd7f..a31d1b3c5315 100644
--- a/servo/components/compositing/headless.rs
+++ b/servo/components/compositing/headless.rs
@@ -8,9 +8,10 @@ use euclid::scale_factor::ScaleFactor;
 use euclid::{Point2D, Size2D};
 use msg::constellation_msg::AnimationState;
 use msg::constellation_msg::CompositorMsg as ConstellationMsg;
-use msg::constellation_msg::{ConstellationChan, WindowSizeData};
+use msg::constellation_msg::WindowSizeData;
 use profile_traits::mem;
 use profile_traits::time;
+use std::sync::mpsc::Sender;
 use util::opts;
 use windowing::WindowEvent;
 
@@ -22,7 +23,7 @@ pub struct NullCompositor {
     /// The port on which we receive messages.
     pub port: Box<CompositorReceiver>,
     /// A channel to the constellation.
-    constellation_chan: ConstellationChan<ConstellationMsg>,
+    constellation_chan: Sender<ConstellationMsg>,
     /// A channel to the time profiler.
     time_profiler_chan: time::ProfilerChan,
     /// A channel to the memory profiler.
@@ -44,8 +45,7 @@ impl NullCompositor {
 
         // Tell the constellation about the initial fake size.
         {
-            let ConstellationChan(ref chan) = compositor.constellation_chan;
-            chan.send(ConstellationMsg::ResizedWindow(WindowSizeData {
+            compositor.constellation_chan.send(ConstellationMsg::ResizedWindow(WindowSizeData {
                 initial_viewport: Size2D::typed(800_f32, 600_f32),
                 visible_viewport: Size2D::typed(800_f32, 600_f32),
                 device_pixel_ratio:
@@ -62,8 +62,7 @@ impl CompositorEventListener for NullCompositor {
         match self.port.recv_compositor_msg() {
             Msg::Exit(chan) => {
                 debug!("shutting down the constellation");
-                let ConstellationChan(ref con_chan) = self.constellation_chan;
-                con_chan.send(ConstellationMsg::Exit).unwrap();
+                self.constellation_chan.send(ConstellationMsg::Exit).unwrap();
                 chan.send(()).unwrap();
             }
 
@@ -100,7 +99,7 @@ impl CompositorEventListener for NullCompositor {
                     AnimationState::NoAnimationCallbacksPresent => {}
                     AnimationState::AnimationCallbacksPresent => {
                         let msg = ConstellationMsg::TickAnimation(pipeline_id);
-                        self.constellation_chan.0.send(msg).unwrap()
+                        self.constellation_chan.send(msg).unwrap()
                     }
                 }
             }
diff --git a/servo/components/compositing/lib.rs b/servo/components/compositing/lib.rs
index a38f1d8490fa..fa2ad24fd60c 100644
--- a/servo/components/compositing/lib.rs
+++ b/servo/components/compositing/lib.rs
@@ -3,7 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #![feature(box_syntax)]
+#![feature(custom_derive)]
 #![feature(iter_cmp)]
+#![feature(plugin)]
 #![feature(slice_bytes)]
 #![feature(vec_push_all)]
 #![feature(mpsc_select)]
@@ -11,6 +13,7 @@
 #![plugin(plugins)]
 
 #![deny(unsafe_code)]
+#![plugin(serde_macros)]
 
 extern crate app_units;
 #[macro_use]
@@ -31,6 +34,7 @@ extern crate core_text;
 
 extern crate devtools_traits;
 extern crate euclid;
+extern crate gaol;
 extern crate gfx;
 extern crate gfx_traits;
 extern crate gleam;
@@ -43,7 +47,10 @@ extern crate net_traits;
 extern crate num;
 extern crate offscreen_gl_context;
 extern crate script_traits;
+extern crate serde;
 extern crate style_traits;
+
+extern crate libc;
 extern crate time;
 extern crate url;
 
@@ -59,4 +66,5 @@ mod timer_scheduler;
 pub mod compositor_task;
 pub mod constellation;
 pub mod pipeline;
+pub mod sandboxing;
 pub mod windowing;
diff --git a/servo/components/compositing/pipeline.rs b/servo/components/compositing/pipeline.rs
index 8742898eaa44..2fbc5c6b0a64 100644
--- a/servo/components/compositing/pipeline.rs
+++ b/servo/components/compositing/pipeline.rs
@@ -14,6 +14,7 @@ use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
 use layers::geometry::DevicePixel;
 use layout_traits::{LayoutControlChan, LayoutTaskFactory};
+use msg::compositor_msg::ScriptToCompositorMsg;
 use msg::constellation_msg::ScriptMsg as ConstellationMsg;
 use msg::constellation_msg::{ConstellationChan, Failure, FrameId, PipelineId, SubpageId};
 use msg::constellation_msg::{LoadData, MozBrowserEvent, WindowSizeData};
@@ -26,7 +27,6 @@ use profile_traits::time;
 use script_traits::{ConstellationControlMsg, InitialScriptState};
 use script_traits::{LayoutControlMsg, NewLayoutInfo, ScriptTaskFactory};
 use script_traits::{TimerEventRequest};
-use std::any::Any;
 use std::mem;
 use std::sync::mpsc::{Receiver, Sender, channel};
 use std::thread;
@@ -34,20 +34,21 @@ use url::Url;
 use util;
 use util::geometry::{PagePx, ViewportPx};
 use util::ipc::OptionalIpcSender;
+use util::opts::{self, Opts};
 use util::prefs;
 
 /// A uniquely-identifiable pipeline of script task, layout task, and paint task.
 pub struct Pipeline {
     pub id: PipelineId,
     pub parent_info: Option<(PipelineId, SubpageId)>,
-    pub script_chan: Sender<ConstellationControlMsg>,
+    pub script_chan: IpcSender<ConstellationControlMsg>,
     /// A channel to layout, for performing reflows and shutdown.
     pub layout_chan: LayoutControlChan,
     /// A channel to the compositor.
     pub compositor_proxy: Box<CompositorProxy + 'static + Send>,
     pub chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
-    pub layout_shutdown_port: Receiver<()>,
-    pub paint_shutdown_port: Receiver<()>,
+    pub layout_shutdown_port: IpcReceiver<()>,
+    pub paint_shutdown_port: IpcReceiver<()>,
     /// URL corresponding to the most recently-loaded page.
     pub url: Url,
     /// The title of the most recently-loaded page.
@@ -63,7 +64,7 @@ pub struct Pipeline {
 #[derive(Clone)]
 pub struct CompositionPipeline {
     pub id: PipelineId,
-    pub script_chan: Sender<ConstellationControlMsg>,
+    pub script_chan: IpcSender<ConstellationControlMsg>,
     pub layout_chan: LayoutControlChan,
     pub chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
 }
@@ -104,7 +105,7 @@ pub struct InitialPipelineState {
     pub device_pixel_ratio: ScaleFactor<ViewportPx, DevicePixel, f32>,
     /// A channel to the script thread, if applicable. If this is `Some`,
     /// then `parent_info` must also be `Some`.
-    pub script_chan: Option<Sender<ConstellationControlMsg>>,
+    pub script_chan: Option<IpcSender<ConstellationControlMsg>>,
     /// Information about the page to load.
     pub load_data: LoadData,
     /// The ID of the pipeline namespace for this script thread.
@@ -115,13 +116,14 @@ impl Pipeline {
     /// Starts a paint task, layout task, and possibly a script task.
     /// Returns the channels wrapped in a struct.
     pub fn create<LTF, STF>(state: InitialPipelineState)
-                            -> (Pipeline, PipelineContent)
+                            -> (Pipeline, UnprivilegedPipelineContent, PrivilegedPipelineContent)
                             where LTF: LayoutTaskFactory, STF: ScriptTaskFactory {
         let (layout_to_paint_chan, layout_to_paint_port) = util::ipc::optional_ipc_channel();
         let (chrome_to_paint_chan, chrome_to_paint_port) = channel();
-        let (paint_shutdown_chan, paint_shutdown_port) = channel();
-        let (layout_shutdown_chan, layout_shutdown_port) = channel();
+        let (paint_shutdown_chan, paint_shutdown_port) = ipc::channel().unwrap();
+        let (layout_shutdown_chan, layout_shutdown_port) = ipc::channel().unwrap();
         let (pipeline_chan, pipeline_port) = ipc::channel().unwrap();
+        let (script_to_compositor_chan, script_to_compositor_port) = ipc::channel().unwrap();
         let mut pipeline_port = Some(pipeline_port);
 
         let failure = Failure {
@@ -148,6 +150,9 @@ impl Pipeline {
             script_to_devtools_chan
         });
 
+        let (layout_content_process_shutdown_chan, layout_content_process_shutdown_port) =
+            ipc::channel().unwrap();
+
         let (script_chan, script_port) = match state.script_chan {
             Some(script_chan) => {
                 let (containing_pipeline_id, subpage_id) =
@@ -157,10 +162,11 @@ impl Pipeline {
                     new_pipeline_id: state.id,
                     subpage_id: subpage_id,
                     load_data: state.load_data.clone(),
-                    paint_chan: box layout_to_paint_chan.clone() as Box<Any + Send>,
+                    paint_chan: layout_to_paint_chan.clone().to_opaque(),
                     failure: failure,
                     pipeline_port: mem::replace(&mut pipeline_port, None).unwrap(),
                     layout_shutdown_chan: layout_shutdown_chan.clone(),
+                    content_process_shutdown_chan: layout_content_process_shutdown_chan.clone(),
                 };
 
                 script_chan.send(ConstellationControlMsg::AttachLayout(new_layout_info))
@@ -168,11 +174,14 @@ impl Pipeline {
                 (script_chan, None)
             }
             None => {
-                let (script_chan, script_port) = channel();
+                let (script_chan, script_port) = ipc::channel().unwrap();
                 (script_chan, Some(script_port))
             }
         };
 
+        let (script_content_process_shutdown_chan, script_content_process_shutdown_port) =
+            ipc::channel().unwrap();
+
         let pipeline = Pipeline::new(state.id,
                                      state.parent_info,
                                      script_chan.clone(),
@@ -184,45 +193,63 @@ impl Pipeline {
                                      state.load_data.url.clone(),
                                      state.window_size);
 
-        let pipeline_content = PipelineContent {
+        let unprivileged_pipeline_content = UnprivilegedPipelineContent {
             id: state.id,
             parent_info: state.parent_info,
-            constellation_chan: state.constellation_chan,
+            constellation_chan: state.constellation_chan.clone(),
             scheduler_chan: state.scheduler_chan,
-            compositor_proxy: state.compositor_proxy,
             devtools_chan: script_to_devtools_chan,
             image_cache_task: state.image_cache_task,
-            font_cache_task: state.font_cache_task,
+            font_cache_task: state.font_cache_task.clone(),
             resource_task: state.resource_task,
             storage_task: state.storage_task,
-            time_profiler_chan: state.time_profiler_chan,
-            mem_profiler_chan: state.mem_profiler_chan,
+            time_profiler_chan: state.time_profiler_chan.clone(),
+            mem_profiler_chan: state.mem_profiler_chan.clone(),
             window_size: window_size,
             script_chan: script_chan,
-            load_data: state.load_data,
+            load_data: state.load_data.clone(),
             failure: failure,
             script_port: script_port,
+            opts: (*opts::get()).clone(),
             layout_to_paint_chan: layout_to_paint_chan,
-            chrome_to_paint_chan: chrome_to_paint_chan,
-            layout_to_paint_port: Some(layout_to_paint_port),
-            chrome_to_paint_port: Some(chrome_to_paint_port),
             pipeline_port: pipeline_port,
-            paint_shutdown_chan: paint_shutdown_chan,
             layout_shutdown_chan: layout_shutdown_chan,
+            paint_shutdown_chan: paint_shutdown_chan.clone(),
+            script_to_compositor_chan: script_to_compositor_chan,
             pipeline_namespace_id: state.pipeline_namespace_id,
+            layout_content_process_shutdown_chan: layout_content_process_shutdown_chan,
+            layout_content_process_shutdown_port: layout_content_process_shutdown_port,
+            script_content_process_shutdown_chan: script_content_process_shutdown_chan,
+            script_content_process_shutdown_port: script_content_process_shutdown_port,
         };
 
-        (pipeline, pipeline_content)
+        let privileged_pipeline_content = PrivilegedPipelineContent {
+            id: state.id,
+            constellation_chan: state.constellation_chan,
+            compositor_proxy: state.compositor_proxy,
+            font_cache_task: state.font_cache_task,
+            time_profiler_chan: state.time_profiler_chan,
+            mem_profiler_chan: state.mem_profiler_chan,
+            load_data: state.load_data,
+            failure: failure,
+            layout_to_paint_port: Some(layout_to_paint_port),
+            chrome_to_paint_chan: chrome_to_paint_chan,
+            chrome_to_paint_port: Some(chrome_to_paint_port),
+            paint_shutdown_chan: paint_shutdown_chan,
+            script_to_compositor_port: Some(script_to_compositor_port),
+        };
+
+        (pipeline, unprivileged_pipeline_content, privileged_pipeline_content)
     }
 
     pub fn new(id: PipelineId,
                parent_info: Option<(PipelineId, SubpageId)>,
-               script_chan: Sender<ConstellationControlMsg>,
+               script_chan: IpcSender<ConstellationControlMsg>,
                layout_chan: LayoutControlChan,
                compositor_proxy: Box<CompositorProxy + 'static + Send>,
                chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
-               layout_shutdown_port: Receiver<()>,
-               paint_shutdown_port: Receiver<()>,
+               layout_shutdown_port: IpcReceiver<()>,
+               paint_shutdown_port: IpcReceiver<()>,
                url: Url,
                size: Option<TypedSize2D<PagePx, f32>>)
                -> Pipeline {
@@ -315,13 +342,14 @@ impl Pipeline {
     }
 }
 
-pub struct PipelineContent {
+#[derive(Deserialize, Serialize)]
+pub struct UnprivilegedPipelineContent {
     id: PipelineId,
     parent_info: Option<(PipelineId, SubpageId)>,
     constellation_chan: ConstellationChan<ConstellationMsg>,
     scheduler_chan: IpcSender<TimerEventRequest>,
-    compositor_proxy: Box<CompositorProxy + Send + 'static>,
     devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
+    script_to_compositor_chan: IpcSender<ScriptToCompositorMsg>,
     image_cache_task: ImageCacheTask,
     font_cache_task: FontCacheTask,
     resource_task: ResourceTask,
@@ -329,39 +357,31 @@ pub struct PipelineContent {
     time_profiler_chan: time::ProfilerChan,
     mem_profiler_chan: profile_mem::ProfilerChan,
     window_size: Option<WindowSizeData>,
-    script_chan: Sender<ConstellationControlMsg>,
+    script_chan: IpcSender<ConstellationControlMsg>,
     load_data: LoadData,
     failure: Failure,
-    script_port: Option<Receiver<ConstellationControlMsg>>,
+    script_port: Option<IpcReceiver<ConstellationControlMsg>>,
     layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
-    chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
-    layout_to_paint_port: Option<Receiver<LayoutToPaintMsg>>,
-    chrome_to_paint_port: Option<Receiver<ChromeToPaintMsg>>,
-    paint_shutdown_chan: Sender<()>,
+    opts: Opts,
+    paint_shutdown_chan: IpcSender<()>,
     pipeline_port: Option<IpcReceiver<LayoutControlMsg>>,
-    layout_shutdown_chan: Sender<()>,
     pipeline_namespace_id: PipelineNamespaceId,
+    layout_shutdown_chan: IpcSender<()>,
+    layout_content_process_shutdown_chan: IpcSender<()>,
+    layout_content_process_shutdown_port: IpcReceiver<()>,
+    script_content_process_shutdown_chan: IpcSender<()>,
+    script_content_process_shutdown_port: IpcReceiver<()>,
 }
 
-impl PipelineContent {
-    pub fn start_all<LTF, STF>(mut self) where LTF: LayoutTaskFactory, STF: ScriptTaskFactory {
+impl UnprivilegedPipelineContent {
+    pub fn start_all<LTF, STF>(mut self, wait_for_completion: bool)
+                               where LTF: LayoutTaskFactory, STF: ScriptTaskFactory {
         let layout_pair = ScriptTaskFactory::create_layout_channel(None::<&mut STF>);
-        let (script_to_compositor_chan, script_to_compositor_port) = ipc::channel().unwrap();
-
-        self.start_paint_task();
-
-        let compositor_proxy_for_script_listener_thread =
-            self.compositor_proxy.clone_compositor_proxy();
-        thread::spawn(move || {
-            compositor_task::run_script_listener_thread(
-                compositor_proxy_for_script_listener_thread,
-                script_to_compositor_port)
-        });
 
         ScriptTaskFactory::create(None::<&mut STF>, InitialScriptState {
             id: self.id,
             parent_info: self.parent_info,
-            compositor: script_to_compositor_chan,
+            compositor: self.script_to_compositor_chan.clone(),
             control_chan: self.script_chan.clone(),
             control_port: mem::replace(&mut self.script_port, None).unwrap(),
             constellation_chan: self.constellation_chan.clone(),
@@ -375,6 +395,7 @@ impl PipelineContent {
             devtools_chan: self.devtools_chan,
             window_size: self.window_size,
             pipeline_namespace_id: self.pipeline_namespace_id,
+            content_process_shutdown_chan: self.script_content_process_shutdown_chan.clone(),
         }, &layout_pair, self.load_data.clone());
 
         LayoutTaskFactory::create(None::<&mut LTF>,
@@ -391,7 +412,49 @@ impl PipelineContent {
                                   self.font_cache_task,
                                   self.time_profiler_chan,
                                   self.mem_profiler_chan,
-                                  self.layout_shutdown_chan);
+                                  self.layout_shutdown_chan,
+                                  self.layout_content_process_shutdown_chan.clone());
+
+        if wait_for_completion {
+            self.script_content_process_shutdown_port.recv().unwrap();
+            self.layout_content_process_shutdown_port.recv().unwrap();
+        }
+    }
+
+    pub fn opts(&self) -> Opts {
+        self.opts.clone()
+    }
+}
+
+pub struct PrivilegedPipelineContent {
+    id: PipelineId,
+    constellation_chan: ConstellationChan<ConstellationMsg>,
+    compositor_proxy: Box<CompositorProxy + Send + 'static>,
+    script_to_compositor_port: Option<IpcReceiver<ScriptToCompositorMsg>>,
+    font_cache_task: FontCacheTask,
+    time_profiler_chan: time::ProfilerChan,
+    mem_profiler_chan: profile_mem::ProfilerChan,
+    load_data: LoadData,
+    failure: Failure,
+    layout_to_paint_port: Option<Receiver<LayoutToPaintMsg>>,
+    chrome_to_paint_chan: Sender<ChromeToPaintMsg>,
+    chrome_to_paint_port: Option<Receiver<ChromeToPaintMsg>>,
+    paint_shutdown_chan: IpcSender<()>,
+}
+
+impl PrivilegedPipelineContent {
+    pub fn start_all(&mut self) {
+        self.start_paint_task();
+
+        let compositor_proxy_for_script_listener_thread =
+            self.compositor_proxy.clone_compositor_proxy();
+        let script_to_compositor_port =
+            mem::replace(&mut self.script_to_compositor_port, None).unwrap();
+        thread::spawn(move || {
+            compositor_task::run_script_listener_thread(
+                compositor_proxy_for_script_listener_thread,
+                script_to_compositor_port)
+        });
     }
 
     pub fn start_paint_task(&mut self) {
diff --git a/servo/components/compositing/sandboxing.rs b/servo/components/compositing/sandboxing.rs
new file mode 100644
index 000000000000..dd02f878ae30
--- /dev/null
+++ b/servo/components/compositing/sandboxing.rs
@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use gaol::platform;
+use gaol::profile::{Operation, PathPattern, Profile};
+use std::path::PathBuf;
+use util::resource_files;
+
+/// Our content process sandbox profile on Mac. As restrictive as possible.
+#[cfg(target_os = "macos")]
+pub fn content_process_sandbox_profile() -> Profile {
+    Profile::new(vec![
+        Operation::FileReadAll(PathPattern::Literal(PathBuf::from("/dev/urandom"))),
+        Operation::FileReadAll(PathPattern::Subpath(resource_files::resources_dir_path())),
+        Operation::FileReadAll(PathPattern::Subpath(PathBuf::from("/Library/Fonts"))),
+        Operation::FileReadAll(PathPattern::Subpath(PathBuf::from("/System/Library/Fonts"))),
+        Operation::FileReadAll(PathPattern::Subpath(PathBuf::from(
+                    "/System/Library/Frameworks/ApplicationServices.framework/"))),
+        Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/"))),
+        Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/Library"))),
+        Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/System"))),
+        Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/etc"))),
+        Operation::SystemInfoRead,
+        Operation::PlatformSpecific(platform::macos::Operation::MachLookup(
+                b"com.apple.FontServer".to_vec())),
+    ]).expect("Failed to create sandbox profile!")
+}
+
+/// Our content process sandbox profile on Linux. As restrictive as possible.
+#[cfg(not(target_os = "macos"))]
+pub fn content_process_sandbox_profile() -> Profile {
+    Profile::new(vec![
+        Operation::FileReadAll(PathPattern::Literal(PathBuf::from("/dev/urandom"))),
+        Operation::FileReadAll(PathPattern::Subpath(resource_files::resources_dir_path())),
+    ]).expect("Failed to create sandbox profile!")
+}
+
diff --git a/servo/components/gfx/font_cache_task.rs b/servo/components/gfx/font_cache_task.rs
index 6122325b6022..578d3f9d9e79 100644
--- a/servo/components/gfx/font_cache_task.rs
+++ b/servo/components/gfx/font_cache_task.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use font_template::{FontTemplate, FontTemplateDescriptor};
-use ipc_channel::ipc;
+use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
 use net_traits::{AsyncResponseTarget, PendingAsyncLoad, ResourceTask, ResponseAction};
 use platform::font_context::FontContextHandle;
@@ -15,7 +15,7 @@ use platform::font_template::FontTemplateData;
 use std::borrow::ToOwned;
 use std::collections::HashMap;
 use std::mem;
-use std::sync::mpsc::{Sender, Receiver, channel};
+use std::sync::mpsc::channel;
 use std::sync::{Arc, Mutex};
 use string_cache::Atom;
 use style::font_face::Source;
@@ -77,15 +77,17 @@ impl FontFamily {
 }
 
 /// Commands that the FontContext sends to the font cache task.
+#[derive(Deserialize, Serialize)]
 pub enum Command {
-    GetFontTemplate(String, FontTemplateDescriptor, Sender<Reply>),
-    GetLastResortFontTemplate(FontTemplateDescriptor, Sender<Reply>),
-    AddWebFont(Atom, Source, Sender<()>),
-    AddDownloadedWebFont(LowercaseString, Url, Vec<u8>, Sender<()>),
-    Exit(Sender<()>),
+    GetFontTemplate(String, FontTemplateDescriptor, IpcSender<Reply>),
+    GetLastResortFontTemplate(FontTemplateDescriptor, IpcSender<Reply>),
+    AddWebFont(Atom, Source, IpcSender<()>),
+    AddDownloadedWebFont(LowercaseString, Url, Vec<u8>, IpcSender<()>),
+    Exit(IpcSender<()>),
 }
 
 /// Reply messages sent from the font cache task to the FontContext caller.
+#[derive(Deserialize, Serialize)]
 pub enum Reply {
     GetFontTemplateReply(Option<Arc<FontTemplateData>>),
 }
@@ -93,8 +95,8 @@ pub enum Reply {
 /// The font cache task itself. It maintains a list of reference counted
 /// font templates that are currently in use.
 struct FontCache {
-    port: Receiver<Command>,
-    channel_to_self: Sender<Command>,
+    port: IpcReceiver<Command>,
+    channel_to_self: IpcSender<Command>,
     generic_fonts: HashMap<LowercaseString, LowercaseString>,
     local_families: HashMap<LowercaseString, FontFamily>,
     web_families: HashMap<LowercaseString, FontFamily>,
@@ -269,14 +271,14 @@ impl FontCache {
 
 /// The public interface to the font cache task, used exclusively by
 /// the per-thread/task FontContext structures.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct FontCacheTask {
-    chan: Sender<Command>,
+    chan: IpcSender<Command>,
 }
 
 impl FontCacheTask {
     pub fn new(resource_task: ResourceTask) -> FontCacheTask {
-        let (chan, port) = channel();
+        let (chan, port) = ipc::channel().unwrap();
 
         let channel_to_self = chan.clone();
         spawn_named("FontCacheTask".to_owned(), move || {
@@ -310,7 +312,7 @@ impl FontCacheTask {
     pub fn find_font_template(&self, family: String, desc: FontTemplateDescriptor)
                                                 -> Option<Arc<FontTemplateData>> {
 
-        let (response_chan, response_port) = channel();
+        let (response_chan, response_port) = ipc::channel().unwrap();
         self.chan.send(Command::GetFontTemplate(family, desc, response_chan)).unwrap();
 
         let reply = response_port.recv().unwrap();
@@ -325,7 +327,7 @@ impl FontCacheTask {
     pub fn last_resort_font_template(&self, desc: FontTemplateDescriptor)
                                                 -> Arc<FontTemplateData> {
 
-        let (response_chan, response_port) = channel();
+        let (response_chan, response_port) = ipc::channel().unwrap();
         self.chan.send(Command::GetLastResortFontTemplate(desc, response_chan)).unwrap();
 
         let reply = response_port.recv().unwrap();
@@ -337,12 +339,12 @@ impl FontCacheTask {
         }
     }
 
-    pub fn add_web_font(&self, family: Atom, src: Source, sender: Sender<()>) {
+    pub fn add_web_font(&self, family: Atom, src: Source, sender: IpcSender<()>) {
         self.chan.send(Command::AddWebFont(family, src, sender)).unwrap();
     }
 
     pub fn exit(&self) {
-        let (response_chan, response_port) = channel();
+        let (response_chan, response_port) = ipc::channel().unwrap();
         self.chan.send(Command::Exit(response_chan)).unwrap();
         response_port.recv().unwrap();
     }
diff --git a/servo/components/gfx/font_template.rs b/servo/components/gfx/font_template.rs
index 843216a81bbf..45becf31d5c3 100644
--- a/servo/components/gfx/font_template.rs
+++ b/servo/components/gfx/font_template.rs
@@ -14,7 +14,7 @@ use style::computed_values::{font_stretch, font_weight};
 /// to be expanded or refactored when we support more of the font styling parameters.
 ///
 /// NB: If you change this, you will need to update `style::properties::compute_font_hash()`.
-#[derive(Clone, Copy, Eq, Hash)]
+#[derive(Clone, Copy, Eq, Hash, Deserialize, Serialize)]
 pub struct FontTemplateDescriptor {
     pub weight: font_weight::T,
     pub stretch: font_stretch::T,
diff --git a/servo/components/gfx/paint_task.rs b/servo/components/gfx/paint_task.rs
index 82b0e75d284d..d3859e306517 100644
--- a/servo/components/gfx/paint_task.rs
+++ b/servo/components/gfx/paint_task.rs
@@ -36,8 +36,7 @@ use std::sync::mpsc::{Receiver, Select, Sender, channel};
 use url::Url;
 use util::geometry::{ExpandToPixelBoundaries, ZERO_POINT};
 use util::opts;
-use util::task::spawn_named;
-use util::task::spawn_named_with_send_on_failure;
+use util::task;
 use util::task_state;
 
 #[derive(Clone, Deserialize, Serialize, HeapSizeOf)]
@@ -255,9 +254,11 @@ impl<C> PaintTask<C> where C: PaintListener + Send + 'static {
                   failure_msg: Failure,
                   time_profiler_chan: time::ProfilerChan,
                   mem_profiler_chan: mem::ProfilerChan,
-                  shutdown_chan: Sender<()>) {
+                  shutdown_chan: IpcSender<()>) {
         let ConstellationChan(c) = constellation_chan.clone();
-        spawn_named_with_send_on_failure(format!("PaintTask {:?}", id), task_state::PAINT, move || {
+        task::spawn_named_with_send_on_failure(format!("PaintTask {:?}", id),
+                                               task_state::PAINT,
+                                               move || {
             {
                 // Ensures that the paint task and graphics context are destroyed before the
                 // shutdown message.
@@ -572,7 +573,7 @@ impl WorkerThreadProxy {
             let (to_worker_sender, to_worker_receiver) = channel();
             let font_cache_task = font_cache_task.clone();
             let time_profiler_chan = time_profiler_chan.clone();
-            spawn_named("PaintWorker".to_owned(), move || {
+            task::spawn_named("PaintWorker".to_owned(), move || {
                 let mut worker_thread = WorkerThread::new(from_worker_sender,
                                                           to_worker_receiver,
                                                           native_display,
diff --git a/servo/components/layout/layout_task.rs b/servo/components/layout/layout_task.rs
index e4cfcefeaf5f..6eced0fd13e7 100644
--- a/servo/components/layout/layout_task.rs
+++ b/servo/components/layout/layout_task.rs
@@ -70,7 +70,7 @@ use util::ipc::OptionalIpcSender;
 use util::logical_geometry::LogicalPoint;
 use util::mem::HeapSizeOf;
 use util::opts;
-use util::task::spawn_named_with_send_on_failure;
+use util::task;
 use util::task_state;
 use util::workqueue::WorkQueue;
 use wrapper::{LayoutDocument, LayoutElement, LayoutNode, ServoLayoutNode};
@@ -137,13 +137,13 @@ pub struct LayoutTask {
     font_cache_receiver: Receiver<()>,
 
     /// The channel on which the font cache can send messages to us.
-    font_cache_sender: Sender<()>,
+    font_cache_sender: IpcSender<()>,
 
     /// The channel on which messages can be sent to the constellation.
     constellation_chan: ConstellationChan<ConstellationMsg>,
 
     /// The channel on which messages can be sent to the script task.
-    script_chan: Sender<ConstellationControlMsg>,
+    script_chan: IpcSender<ConstellationControlMsg>,
 
     /// The channel on which messages can be sent to the painting task.
     paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
@@ -219,17 +219,18 @@ impl LayoutTaskFactory for LayoutTask {
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: ConstellationChan<ConstellationMsg>,
               failure_msg: Failure,
-              script_chan: Sender<ConstellationControlMsg>,
+              script_chan: IpcSender<ConstellationControlMsg>,
               paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_task: ImageCacheTask,
               font_cache_task: FontCacheTask,
               time_profiler_chan: time::ProfilerChan,
               mem_profiler_chan: mem::ProfilerChan,
-              shutdown_chan: Sender<()>) {
+              shutdown_chan: IpcSender<()>,
+              content_process_shutdown_chan: IpcSender<()>) {
         let ConstellationChan(con_chan) = constellation_chan.clone();
-        spawn_named_with_send_on_failure(format!("LayoutTask {:?}", id),
-                                         task_state::LAYOUT,
-                                         move || {
+        task::spawn_named_with_send_on_failure(format!("LayoutTask {:?}", id),
+                                               task_state::LAYOUT,
+                                               move || {
             { // Ensures layout task is destroyed before we send shutdown message
                 let sender = chan.sender();
                 let layout = LayoutTask::new(id,
@@ -250,7 +251,8 @@ impl LayoutTaskFactory for LayoutTask {
                     layout.start();
                 }, reporter_name, sender, Msg::CollectReports);
             }
-            shutdown_chan.send(()).unwrap();
+            let _ = shutdown_chan.send(());
+            let _ = content_process_shutdown_chan.send(());
         }, ConstellationMsg::Failure(failure_msg), con_chan);
     }
 }
@@ -318,12 +320,12 @@ impl<'a, 'b: 'a> RwData<'a, 'b> {
 fn add_font_face_rules(stylesheet: &Stylesheet,
                        device: &Device,
                        font_cache_task: &FontCacheTask,
-                       font_cache_sender: &Sender<()>,
+                       font_cache_sender: &IpcSender<()>,
                        outstanding_web_fonts_counter: &Arc<AtomicUsize>) {
     for font_face in stylesheet.effective_rules(&device).font_face() {
         for source in &font_face.sources {
             if opts::get().load_webfonts_synchronously {
-                let (sender, receiver) = channel();
+                let (sender, receiver) = ipc::channel().unwrap();
                 font_cache_task.add_web_font(font_face.family.clone(),
                                              (*source).clone(),
                                              sender);
@@ -346,7 +348,7 @@ impl LayoutTask {
            port: Receiver<Msg>,
            pipeline_port: IpcReceiver<LayoutControlMsg>,
            constellation_chan: ConstellationChan<ConstellationMsg>,
-           script_chan: Sender<ConstellationControlMsg>,
+           script_chan: IpcSender<ConstellationControlMsg>,
            paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
            image_cache_task: ImageCacheTask,
            font_cache_task: FontCacheTask,
@@ -375,7 +377,10 @@ impl LayoutTask {
         let image_cache_receiver =
             ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_image_cache_receiver);
 
-        let (font_cache_sender, font_cache_receiver) = channel();
+        // Ask the router to proxy IPC messages from the font cache task to the layout thread.
+        let (ipc_font_cache_sender, ipc_font_cache_receiver) = ipc::channel().unwrap();
+        let font_cache_receiver =
+            ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_font_cache_receiver);
 
         let stylist = box Stylist::new(device);
         let outstanding_web_fonts_counter = Arc::new(AtomicUsize::new(0));
@@ -383,7 +388,7 @@ impl LayoutTask {
             add_font_face_rules(stylesheet,
                                 &stylist.device,
                                 &font_cache_task,
-                                &font_cache_sender,
+                                &ipc_font_cache_sender,
                                 &outstanding_web_fonts_counter);
         }
 
@@ -404,7 +409,7 @@ impl LayoutTask {
             image_cache_receiver: image_cache_receiver,
             image_cache_sender: ImageCacheChan(ipc_image_cache_sender),
             font_cache_receiver: font_cache_receiver,
-            font_cache_sender: font_cache_sender,
+            font_cache_sender: ipc_font_cache_sender,
             canvas_layers_receiver: canvas_layers_receiver,
             canvas_layers_sender: canvas_layers_sender,
             parallel_traversal: parallel_traversal,
@@ -668,14 +673,13 @@ impl LayoutTask {
                                   info.constellation_chan,
                                   info.failure,
                                   info.script_chan.clone(),
-                                  *info.paint_chan
-                                       .downcast::<OptionalIpcSender<LayoutToPaintMsg>>()
-                                       .unwrap(),
+                                  info.paint_chan.to::<LayoutToPaintMsg>(),
                                   self.image_cache_task.clone(),
                                   self.font_cache_task.clone(),
                                   self.time_profiler_chan.clone(),
                                   self.mem_profiler_chan.clone(),
-                                  info.layout_shutdown_chan);
+                                  info.layout_shutdown_chan,
+                                  info.content_process_shutdown_chan);
     }
 
     /// Enters a quiescent state in which no new messages will be processed until an `ExitNow` is
diff --git a/servo/components/layout_traits/lib.rs b/servo/components/layout_traits/lib.rs
index 9205d4205837..50024754ba45 100644
--- a/servo/components/layout_traits/lib.rs
+++ b/servo/components/layout_traits/lib.rs
@@ -29,7 +29,6 @@ use msg::constellation_msg::{ConstellationChan, Failure, PipelineId};
 use net_traits::image_cache_task::ImageCacheTask;
 use profile_traits::{mem, time};
 use script_traits::{LayoutControlMsg, ConstellationControlMsg, OpaqueScriptLayoutChannel};
-use std::sync::mpsc::Sender;
 use url::Url;
 use util::ipc::OptionalIpcSender;
 
@@ -49,11 +48,12 @@ pub trait LayoutTaskFactory {
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: ConstellationChan<ConstellationMsg>,
               failure_msg: Failure,
-              script_chan: Sender<ConstellationControlMsg>,
+              script_chan: IpcSender<ConstellationControlMsg>,
               layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_task: ImageCacheTask,
               font_cache_task: FontCacheTask,
               time_profiler_chan: time::ProfilerChan,
               mem_profiler_chan: mem::ProfilerChan,
-              shutdown_chan: Sender<()>);
+              shutdown_chan: IpcSender<()>,
+              content_process_shutdown_chan: IpcSender<()>);
 }
diff --git a/servo/components/msg/constellation_msg.rs b/servo/components/msg/constellation_msg.rs
index 59da1f175db9..e01ff1c93475 100644
--- a/servo/components/msg/constellation_msg.rs
+++ b/servo/components/msg/constellation_msg.rs
@@ -11,13 +11,14 @@ use euclid::scale_factor::ScaleFactor;
 use euclid::size::{Size2D, TypedSize2D};
 use hyper::header::Headers;
 use hyper::method::Method;
-use ipc_channel::ipc::{IpcSender, IpcSharedMemory};
+use ipc_channel::ipc::{self, IpcReceiver, IpcSender, IpcSharedMemory};
 use layers::geometry::DevicePixel;
 use offscreen_gl_context::GLContextAttributes;
+use serde::{Deserialize, Serialize};
 use std::cell::Cell;
 use std::collections::HashMap;
 use std::fmt;
-use std::sync::mpsc::{Receiver, Sender, channel};
+use std::sync::mpsc::channel;
 use style_traits::viewport::ViewportConstraints;
 use url::Url;
 use util::cursor::Cursor;
@@ -25,16 +26,17 @@ use util::geometry::{PagePx, ViewportPx};
 use util::mem::HeapSizeOf;
 use webdriver_msg::{LoadStatus, WebDriverScriptCommand};
 
-pub struct ConstellationChan<T>(pub Sender<T>);
+#[derive(Deserialize, Serialize)]
+pub struct ConstellationChan<T: Deserialize + Serialize>(pub IpcSender<T>);
 
-impl<T> ConstellationChan<T> {
-    pub fn new() -> (Receiver<T>, ConstellationChan<T>) {
-        let (chan, port) = channel();
+impl<T: Deserialize + Serialize> ConstellationChan<T> {
+    pub fn new() -> (IpcReceiver<T>, ConstellationChan<T>) {
+        let (chan, port) = ipc::channel().unwrap();
         (port, ConstellationChan(chan))
     }
 }
 
-impl<T> Clone for ConstellationChan<T> {
+impl<T: Serialize + Deserialize> Clone for ConstellationChan<T> {
     fn clone(&self) -> ConstellationChan<T> {
         ConstellationChan(self.0.clone())
     }
diff --git a/servo/components/profile/time.rs b/servo/components/profile/time.rs
index 0de493368afe..8092be811bde 100644
--- a/servo/components/profile/time.rs
+++ b/servo/components/profile/time.rs
@@ -100,6 +100,7 @@ impl Formattable for ProfilerCategory {
             ProfilerCategory::ScriptUpdateReplacedElement => "Script Update Replaced Element",
             ProfilerCategory::ScriptSetViewport => "Script Set Viewport",
             ProfilerCategory::ScriptTimerEvent => "Script Timer Event",
+            ProfilerCategory::ScriptStylesheetLoad => "Script Stylesheet Load",
             ProfilerCategory::ScriptWebSocketEvent => "Script Web Socket Event",
             ProfilerCategory::ScriptWorkerEvent => "Script Worker Event",
             ProfilerCategory::ApplicationHeartbeat => "Application Heartbeat",
diff --git a/servo/components/profile_traits/mem.rs b/servo/components/profile_traits/mem.rs
index caf7ba8a7934..9fc78febdd69 100644
--- a/servo/components/profile_traits/mem.rs
+++ b/servo/components/profile_traits/mem.rs
@@ -25,7 +25,7 @@ impl<T> OpaqueSender<T> for Sender<T> {
 
 /// Front-end representation of the profiler used to communicate with the
 /// profiler.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct ProfilerChan(pub IpcSender<ProfilerMsg>);
 
 impl ProfilerChan {
diff --git a/servo/components/profile_traits/time.rs b/servo/components/profile_traits/time.rs
index 5ebfcc18e460..c29bbe7993fa 100644
--- a/servo/components/profile_traits/time.rs
+++ b/servo/components/profile_traits/time.rs
@@ -60,15 +60,16 @@ pub enum ProfilerCategory {
     ScriptDevtoolsMsg,
     ScriptDocumentEvent,
     ScriptDomEvent,
+    ScriptEvent,
     ScriptFileRead,
     ScriptImageCacheMsg,
     ScriptInputEvent,
     ScriptNetworkEvent,
     ScriptResize,
-    ScriptEvent,
-    ScriptUpdateReplacedElement,
     ScriptSetViewport,
     ScriptTimerEvent,
+    ScriptStylesheetLoad,
+    ScriptUpdateReplacedElement,
     ScriptWebSocketEvent,
     ScriptWorkerEvent,
     ApplicationHeartbeat,
diff --git a/servo/components/script/dom/bindings/trace.rs b/servo/components/script/dom/bindings/trace.rs
index efb0952e3dcc..e893f284978e 100644
--- a/servo/components/script/dom/bindings/trace.rs
+++ b/servo/components/script/dom/bindings/trace.rs
@@ -53,7 +53,7 @@ use js::jsval::JSVal;
 use js::rust::Runtime;
 use layout_interface::{LayoutChan, LayoutRPC};
 use libc;
-use msg::constellation_msg::ConstellationChan;
+use msg::constellation_msg::{ConstellationChan, ScriptMsg};
 use msg::constellation_msg::{PipelineId, SubpageId, WindowSizeData, WorkerId};
 use net_traits::Metadata;
 use net_traits::image::base::Image;
@@ -275,7 +275,6 @@ no_jsmanaged_fields!(WorkerId);
 no_jsmanaged_fields!(QuirksMode);
 no_jsmanaged_fields!(Runtime);
 no_jsmanaged_fields!(Headers, Method);
-no_jsmanaged_fields!(ConstellationChan<ConstellationMsg>);
 no_jsmanaged_fields!(LayoutChan);
 no_jsmanaged_fields!(WindowProxyHandler);
 no_jsmanaged_fields!(UntrustedNodeAddress);
@@ -299,6 +298,13 @@ no_jsmanaged_fields!(AttrIdentifier);
 no_jsmanaged_fields!(AttrValue);
 no_jsmanaged_fields!(ElementSnapshot);
 
+impl JSTraceable for ConstellationChan<ScriptMsg> {
+    #[inline]
+    fn trace(&self, _trc: *mut JSTracer) {
+        // Do nothing
+    }
+}
+
 impl JSTraceable for Box<ScriptChan + Send> {
     #[inline]
     fn trace(&self, _trc: *mut JSTracer) {
diff --git a/servo/components/script/layout_interface.rs b/servo/components/script/layout_interface.rs
index cf9bae13e3b0..4a78e23e23c5 100644
--- a/servo/components/script/layout_interface.rs
+++ b/servo/components/script/layout_interface.rs
@@ -29,6 +29,8 @@ use string_cache::Atom;
 use style::animation::PropertyAnimation;
 use style::stylesheets::Stylesheet;
 use url::Url;
+use util::ipc::OptionalOpaqueIpcSender;
+
 pub use dom::node::TrustedNodeAddress;
 
 /// Asynchronous messages that script can send to layout.
@@ -254,8 +256,9 @@ pub struct NewLayoutTaskInfo {
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     pub constellation_chan: ConstellationChan<ConstellationMsg>,
     pub failure: Failure,
-    pub script_chan: Sender<ConstellationControlMsg>,
+    pub script_chan: IpcSender<ConstellationControlMsg>,
     pub image_cache_task: ImageCacheTask,
-    pub paint_chan: Box<Any + Send>,
-    pub layout_shutdown_chan: Sender<()>,
+    pub paint_chan: OptionalOpaqueIpcSender,
+    pub layout_shutdown_chan: IpcSender<()>,
+    pub content_process_shutdown_chan: IpcSender<()>,
 }
diff --git a/servo/components/script/script_task.rs b/servo/components/script/script_task.rs
index 5f881601bd76..043c0574be13 100644
--- a/servo/components/script/script_task.rs
+++ b/servo/components/script/script_task.rs
@@ -104,7 +104,7 @@ use time::{Tm, now};
 use url::{Url, UrlParser};
 use util::opts;
 use util::str::DOMString;
-use util::task::spawn_named_with_send_on_failure;
+use util::task;
 use util::task_state;
 use webdriver_handlers;
 
@@ -232,8 +232,9 @@ pub enum ScriptTaskEventCategory {
     Resize,
     ScriptEvent,
     TimerEvent,
-    UpdateReplacedElement,
     SetViewport,
+    StylesheetLoad,
+    UpdateReplacedElement,
     WebSocketEvent,
     WorkerEvent,
 }
@@ -396,7 +397,7 @@ pub struct ScriptTask {
     chan: MainThreadScriptChan,
 
     /// A channel to hand out to tasks that need to respond to a message from the script task.
-    control_chan: Sender<ConstellationControlMsg>,
+    control_chan: IpcSender<ConstellationControlMsg>,
 
     /// The port on which the constellation and layout tasks can communicate with the
     /// script task.
@@ -438,6 +439,8 @@ pub struct ScriptTask {
     scheduler_chan: IpcSender<TimerEventRequest>,
     timer_event_chan: Sender<TimerEvent>,
     timer_event_port: Receiver<TimerEvent>,
+
+    content_process_shutdown_chan: IpcSender<()>,
 }
 
 /// In the event of task failure, all data on the stack runs its destructor. However, there
@@ -484,7 +487,8 @@ impl ScriptTaskFactory for ScriptTask {
         ScriptLayoutChan::new(chan, port)
     }
 
-    fn clone_layout_channel(_phantom: Option<&mut ScriptTask>, pair: &OpaqueScriptLayoutChannel) -> Box<Any + Send> {
+    fn clone_layout_channel(_phantom: Option<&mut ScriptTask>, pair: &OpaqueScriptLayoutChannel)
+                            -> Box<Any + Send> {
         box pair.sender() as Box<Any + Send>
     }
 
@@ -496,9 +500,10 @@ impl ScriptTaskFactory for ScriptTask {
         let (script_chan, script_port) = channel();
         let layout_chan = LayoutChan(layout_chan.sender());
         let failure_info = state.failure_info;
-        spawn_named_with_send_on_failure(format!("ScriptTask {:?}", state.id), task_state::SCRIPT, move || {
+        task::spawn_named_with_send_on_failure(format!("ScriptTask {:?}", state.id),
+                                               task_state::SCRIPT,
+                                               move || {
             PipelineNamespace::install(state.pipeline_namespace_id);
-
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);
             let chan = MainThreadScriptChan(script_chan);
@@ -524,6 +529,7 @@ impl ScriptTaskFactory for ScriptTask {
             let reporter_name = format!("script-reporter-{}", id);
             mem_profiler_chan.run_with_memory_reporting(|| {
                 script_task.start();
+                let _ = script_task.content_process_shutdown_chan.send(());
             }, reporter_name, channel_for_reporter, CommonScriptMsg::CollectReports);
 
             // This must always be the very last operation performed before the task completes
@@ -636,6 +642,9 @@ impl ScriptTask {
 
         let (timer_event_chan, timer_event_port) = channel();
 
+        // Ask the router to proxy IPC messages from the control port to us.
+        let control_port = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(state.control_port);
+
         ScriptTask {
             page: DOMRefCell::new(None),
             incomplete_loads: DOMRefCell::new(vec!()),
@@ -650,7 +659,7 @@ impl ScriptTask {
             port: port,
             chan: chan,
             control_chan: state.control_chan,
-            control_port: state.control_port,
+            control_port: control_port,
             constellation_chan: state.constellation_chan,
             compositor: DOMRefCell::new(state.compositor),
             time_profiler_chan: state.time_profiler_chan,
@@ -667,6 +676,8 @@ impl ScriptTask {
             scheduler_chan: state.scheduler_chan,
             timer_event_chan: timer_event_chan,
             timer_event_port: timer_event_port,
+
+            content_process_shutdown_chan: state.content_process_shutdown_chan,
         }
     }
 
@@ -940,7 +951,10 @@ impl ScriptTask {
                 ScriptTaskEventCategory::NetworkEvent => ProfilerCategory::ScriptNetworkEvent,
                 ScriptTaskEventCategory::Resize => ProfilerCategory::ScriptResize,
                 ScriptTaskEventCategory::ScriptEvent => ProfilerCategory::ScriptEvent,
-                ScriptTaskEventCategory::UpdateReplacedElement => ProfilerCategory::ScriptUpdateReplacedElement,
+                ScriptTaskEventCategory::UpdateReplacedElement => {
+                    ProfilerCategory::ScriptUpdateReplacedElement
+                }
+                ScriptTaskEventCategory::StylesheetLoad => ProfilerCategory::ScriptStylesheetLoad,
                 ScriptTaskEventCategory::SetViewport => ProfilerCategory::ScriptSetViewport,
                 ScriptTaskEventCategory::TimerEvent => ProfilerCategory::ScriptTimerEvent,
                 ScriptTaskEventCategory::WebSocketEvent => ProfilerCategory::ScriptWebSocketEvent,
@@ -1185,6 +1199,7 @@ impl ScriptTask {
             failure,
             pipeline_port,
             layout_shutdown_chan,
+            content_process_shutdown_chan,
         } = new_layout_info;
 
         let layout_pair = ScriptTask::create_layout_channel(None::<&mut ScriptTask>);
@@ -1204,6 +1219,7 @@ impl ScriptTask {
             script_chan: self.control_chan.clone(),
             image_cache_task: self.image_cache_task.clone(),
             layout_shutdown_chan: layout_shutdown_chan,
+            content_process_shutdown_chan: content_process_shutdown_chan,
         };
 
         let page = self.root_page();
diff --git a/servo/components/script_traits/lib.rs b/servo/components/script_traits/lib.rs
index 337f07fda056..995045e6e17f 100644
--- a/servo/components/script_traits/lib.rs
+++ b/servo/components/script_traits/lib.rs
@@ -41,7 +41,7 @@ use net_traits::image_cache_task::ImageCacheTask;
 use net_traits::storage_task::StorageTask;
 use profile_traits::mem;
 use std::any::Any;
-use std::sync::mpsc::{Receiver, Sender};
+use util::ipc::OptionalOpaqueIpcSender;
 use util::mem::HeapSizeOf;
 
 /// The address of a node. Layout sends these back. They must be validated via
@@ -68,6 +68,7 @@ pub enum LayoutControlMsg {
 }
 
 /// The initial data associated with a newly-created framed pipeline.
+#[derive(Deserialize, Serialize)]
 pub struct NewLayoutInfo {
     /// Id of the parent of this new pipeline.
     pub containing_pipeline_id: PipelineId,
@@ -77,21 +78,21 @@ pub struct NewLayoutInfo {
     pub subpage_id: SubpageId,
     /// Network request data which will be initiated by the script task.
     pub load_data: LoadData,
-    /// The paint channel, cast to `Box<Any>`.
-    ///
-    /// TODO(pcwalton): When we convert this to use IPC, this will need to become an
-    /// `IpcAnySender`.
-    pub paint_chan: Box<Any + Send>,
+    /// The paint channel, cast to `OptionalOpaqueIpcSender`. This is really an
+    /// `Sender<LayoutToPaintMsg>`.
+    pub paint_chan: OptionalOpaqueIpcSender,
     /// Information on what to do on task failure.
     pub failure: Failure,
     /// A port on which layout can receive messages from the pipeline.
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     /// A shutdown channel so that layout can notify others when it's done.
-    pub layout_shutdown_chan: Sender<()>,
+    pub layout_shutdown_chan: IpcSender<()>,
+    /// A shutdown channel so that layout can tell the content process to shut down when it's done.
+    pub content_process_shutdown_chan: IpcSender<()>,
 }
 
 /// Used to determine if a script has any pending asynchronous activity.
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Deserialize, Serialize)]
 pub enum ScriptState {
     /// The document has been loaded.
     DocumentLoaded,
@@ -100,6 +101,7 @@ pub enum ScriptState {
 }
 
 /// Messages sent from the constellation or layout to the script task.
+#[derive(Deserialize, Serialize)]
 pub enum ConstellationControlMsg {
     /// Gives a channel and ID to a layout task, as well as the ID of that layout's parent
     AttachLayout(NewLayoutInfo),
@@ -135,11 +137,11 @@ pub enum ConstellationControlMsg {
     /// reflowed.
     WebFontLoaded(PipelineId),
     /// Get the current state of the script task for a given pipeline.
-    GetCurrentState(Sender<ScriptState>, PipelineId),
+    GetCurrentState(IpcSender<ScriptState>, PipelineId),
 }
 
 /// The mouse button involved in the event.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub enum MouseButton {
     /// The left mouse button.
     Left,
@@ -150,7 +152,7 @@ pub enum MouseButton {
 }
 
 /// The type of input represented by a multi-touch event.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub enum TouchEventType {
     /// A new touch point came in contact with the screen.
     Down,
@@ -165,10 +167,11 @@ pub enum TouchEventType {
 /// An opaque identifier for a touch point.
 ///
 /// http://w3c.github.io/touch-events/#widl-Touch-identifier
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Deserialize, Serialize)]
 pub struct TouchId(pub i32);
 
 /// Events from the compositor that the script task needs to know about
+#[derive(Deserialize, Serialize)]
 pub enum CompositorEvent {
     /// The window was resized.
     ResizeEvent(WindowSizeData),
@@ -250,9 +253,9 @@ pub struct InitialScriptState {
     /// The compositor.
     pub compositor: IpcSender<ScriptToCompositorMsg>,
     /// A channel with which messages can be sent to us (the script task).
-    pub control_chan: Sender<ConstellationControlMsg>,
+    pub control_chan: IpcSender<ConstellationControlMsg>,
     /// A port on which messages sent by the constellation to script can be received.
-    pub control_port: Receiver<ConstellationControlMsg>,
+    pub control_port: IpcReceiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
     pub constellation_chan: ConstellationChan<ConstellationMsg>,
     /// A channel to schedule timer events.
@@ -275,8 +278,14 @@ pub struct InitialScriptState {
     pub window_size: Option<WindowSizeData>,
     /// The ID of the pipeline namespace for this script thread.
     pub pipeline_namespace_id: PipelineNamespaceId,
+    /// A ping will be sent on this channel once the script thread shuts down.
+    pub content_process_shutdown_chan: IpcSender<()>,
 }
 
+/// Encapsulates external communication with the script task.
+#[derive(Clone, Deserialize, Serialize)]
+pub struct ScriptControlChan(pub IpcSender<ConstellationControlMsg>);
+
 /// This trait allows creating a `ScriptTask` without depending on the `script`
 /// crate.
 pub trait ScriptTaskFactory {
diff --git a/servo/components/servo/Cargo.lock b/servo/components/servo/Cargo.lock
index 598fcd0bff82..92b083fdf50f 100644
--- a/servo/components/servo/Cargo.lock
+++ b/servo/components/servo/Cargo.lock
@@ -11,11 +11,13 @@ dependencies = [
  "devtools_traits 0.0.1",
  "env_logger 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gfx_tests 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "glutin_app 0.0.1",
  "image 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout 0.0.1",
  "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -261,6 +263,7 @@ dependencies = [
  "core-text 0.1.0 (git+https://github.com/servo/core-text-rs)",
  "devtools_traits 0.0.1",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gfx_traits 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -268,6 +271,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout_traits 0.0.1",
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
@@ -276,6 +280,8 @@ dependencies = [
  "plugins 0.0.1",
  "profile_traits 0.0.1",
  "script_traits 0.0.1",
+ "serde 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -600,6 +606,16 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "gaol"
+version = "0.0.1"
+source = "git+https://github.com/pcwalton/gaol#71865ff8a1824cbc1cbee4d388d56c5ba1b5ffc2"
+dependencies = [
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "gcc"
 version = "0.3.16"
diff --git a/servo/components/servo/Cargo.toml b/servo/components/servo/Cargo.toml
index 6a8bb74972b4..b17a137a16c5 100644
--- a/servo/components/servo/Cargo.toml
+++ b/servo/components/servo/Cargo.toml
@@ -129,6 +129,12 @@ features = [ "serde_serialization" ]
 version = "0.3"
 features = ["plugins"]
 
+[dependencies.gaol]
+git = "https://github.com/pcwalton/gaol"
+
+[dependencies.ipc-channel]
+git = "https://github.com/pcwalton/ipc-channel"
+
 [dependencies.layers]
 git = "https://github.com/servo/rust-layers"
 features = ["plugins"]
diff --git a/servo/components/servo/lib.rs b/servo/components/servo/lib.rs
index c43a22f2b216..4e5af217b5ac 100644
--- a/servo/components/servo/lib.rs
+++ b/servo/components/servo/lib.rs
@@ -17,6 +17,8 @@
 // The `Browser` is fed events from a generic type that implements the
 // `WindowMethods` trait.
 
+extern crate gaol;
+
 #[macro_use]
 extern crate util as _util;
 
@@ -29,6 +31,7 @@ mod export {
     extern crate euclid;
     extern crate gfx;
     extern crate gleam;
+    extern crate ipc_channel;
     extern crate layers;
     extern crate layout;
     extern crate msg;
@@ -48,22 +51,25 @@ extern crate libc;
 extern crate webdriver_server;
 
 #[cfg(feature = "webdriver")]
-fn webdriver(port: u16, constellation: msg::constellation_msg::ConstellationChan<ConstellationMsg>) {
-    webdriver_server::start_server(port, constellation.clone());
+fn webdriver(port: u16, constellation: Sender<ConstellationMsg>) {
+    webdriver_server::start_server(port, constellation);
 }
 
 #[cfg(not(feature = "webdriver"))]
-fn webdriver(_port: u16, _constellation: msg::constellation_msg::ConstellationChan<ConstellationMsg>) { }
+fn webdriver(_port: u16, _constellation: Sender<ConstellationMsg>) { }
 
 use compositing::CompositorEventListener;
 use compositing::compositor_task::InitialCompositorState;
 use compositing::constellation::InitialConstellationState;
+use compositing::pipeline::UnprivilegedPipelineContent;
+use compositing::sandboxing;
 use compositing::windowing::WindowEvent;
 use compositing::windowing::WindowMethods;
 use compositing::{CompositorProxy, CompositorTask, Constellation};
+use gaol::sandbox::{ChildSandbox, ChildSandboxMethods};
 use gfx::font_cache_task::FontCacheTask;
+use ipc_channel::ipc::{self, IpcSender};
 use msg::constellation_msg::CompositorMsg as ConstellationMsg;
-use msg::constellation_msg::ConstellationChan;
 use net::image_cache_task::new_image_cache_task;
 use net::resource_task::new_resource_task;
 use net::storage_task::StorageTaskFactory;
@@ -86,6 +92,7 @@ pub use export::devtools_traits;
 pub use export::euclid;
 pub use export::gfx;
 pub use export::gleam::gl;
+pub use export::ipc_channel;
 pub use export::layers;
 pub use export::layout;
 pub use export::msg;
@@ -193,7 +200,7 @@ fn create_constellation(opts: opts::Opts,
                         time_profiler_chan: time::ProfilerChan,
                         mem_profiler_chan: mem::ProfilerChan,
                         devtools_chan: Option<Sender<devtools_traits::DevtoolsControlMsg>>,
-                        supports_clipboard: bool) -> ConstellationChan<ConstellationMsg> {
+                        supports_clipboard: bool) -> Sender<ConstellationMsg> {
     let resource_task = new_resource_task(opts.user_agent.clone(), devtools_chan.clone());
 
     let image_cache_task = new_image_cache_task(resource_task.clone());
@@ -218,11 +225,33 @@ fn create_constellation(opts: opts::Opts,
     // Send the URL command to the constellation.
     match opts.url {
         Some(url) => {
-            let ConstellationChan(ref chan) = constellation_chan;
-            chan.send(ConstellationMsg::InitLoadUrl(url)).unwrap();
+            constellation_chan.send(ConstellationMsg::InitLoadUrl(url)).unwrap();
         },
         None => ()
     };
 
     constellation_chan
 }
+
+/// Content process entry point.
+pub fn run_content_process(token: String) {
+    let (unprivileged_content_sender, unprivileged_content_receiver) =
+        ipc::channel::<UnprivilegedPipelineContent>().unwrap();
+    let connection_bootstrap: IpcSender<IpcSender<UnprivilegedPipelineContent>> =
+        IpcSender::connect(token).unwrap();
+    connection_bootstrap.send(unprivileged_content_sender).unwrap();
+
+    let unprivileged_content = unprivileged_content_receiver.recv().unwrap();
+    opts::set_defaults(unprivileged_content.opts());
+
+    // Enter the sandbox if necessary.
+    if opts::get().sandbox {
+        ChildSandbox::new(sandboxing::content_process_sandbox_profile()).activate().unwrap();
+    }
+
+    script::init();
+
+    unprivileged_content.start_all::<layout::layout_task::LayoutTask,
+                                     script::script_task::ScriptTask>(true);
+}
+
diff --git a/servo/components/servo/main.rs b/servo/components/servo/main.rs
index 45a64d747842..437df3108325 100644
--- a/servo/components/servo/main.rs
+++ b/servo/components/servo/main.rs
@@ -39,7 +39,7 @@ use offscreen_gl_context::GLContext;
 use servo::Browser;
 use servo::compositing::windowing::WindowEvent;
 use servo::net_traits::hosts;
-use servo::util::opts;
+use servo::util::opts::{self, ArgumentParsingResult};
 use std::rc::Rc;
 
 #[cfg(not(target_os = "android"))]
@@ -52,11 +52,17 @@ fn load_gl_when_headless() {}
 
 fn main() {
     // Parse the command line options and store them globally
-    opts::from_cmdline_args(&*args());
+    let opts_result = opts::from_cmdline_args(&*args());
 
-    if opts::get().is_running_problem_test && ::std::env::var("RUST_LOG").is_err() {
-        ::std::env::set_var("RUST_LOG", "compositing::constellation");
-    }
+    let content_process_token = if let ArgumentParsingResult::ContentProcess(token) = opts_result {
+        Some(token)
+    } else {
+        if opts::get().is_running_problem_test && ::std::env::var("RUST_LOG").is_err() {
+            ::std::env::set_var("RUST_LOG", "compositing::constellation");
+        }
+
+        None
+    };
 
     env_logger::init().unwrap();
 
@@ -65,6 +71,10 @@ fn main() {
     // Possibly interpret the `HOST_FILE` environment variable
     hosts::global_init();
 
+    if let Some(token) = content_process_token {
+        return servo::run_content_process(token)
+    }
+
     let window = if opts::get().headless {
         // Load gl functions even when in headless mode,
         // to avoid crashing with webgl
diff --git a/servo/components/util/ipc.rs b/servo/components/util/ipc.rs
index 20c80cf042bb..be0196abdaf8 100644
--- a/servo/components/util/ipc.rs
+++ b/servo/components/util/ipc.rs
@@ -2,18 +2,20 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::ipc::{self, IpcSender, OpaqueIpcSender};
 use ipc_channel::router::ROUTER;
 use opts;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
-use std::any::Any;
+use std::any::{Any, TypeId};
 use std::collections::HashMap;
+use std::marker::Reflect;
+use std::mem;
 use std::sync::Mutex;
 use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize, Ordering};
 use std::sync::mpsc::{self, Receiver, Sender};
 
 lazy_static! {
-    static ref IN_PROCESS_SENDERS: Mutex<HashMap<usize, Box<Any + Send>>> =
+    static ref IN_PROCESS_SENDERS: Mutex<HashMap<usize, OpaqueSender>> =
         Mutex::new(HashMap::new());
 }
 
@@ -31,6 +33,17 @@ impl<T> OptionalIpcSender<T> where T: Deserialize + Serialize + Send + Any {
             OptionalIpcSender::InProcess(ref sender) => sender.send(value).map_err(|_| ()),
         }
     }
+
+    pub fn to_opaque(self) -> OptionalOpaqueIpcSender {
+        match self {
+            OptionalIpcSender::OutOfProcess(ipc_sender) => {
+                OptionalOpaqueIpcSender::OutOfProcess(ipc_sender.to_opaque())
+            }
+            OptionalIpcSender::InProcess(sender) => {
+                OptionalOpaqueIpcSender::InProcess(OpaqueSender::new(sender))
+            }
+        }
+    }
 }
 
 impl<T> Clone for OptionalIpcSender<T> where T: Deserialize + Serialize + Send + Any {
@@ -49,18 +62,13 @@ impl<T> Clone for OptionalIpcSender<T> where T: Deserialize + Serialize + Send +
 impl<T> Deserialize for OptionalIpcSender<T> where T: Deserialize + Serialize + Send + Any {
     fn deserialize<D>(deserializer: &mut D)
                       -> Result<OptionalIpcSender<T>, D::Error> where D: Deserializer {
-        if opts::get().multiprocess {
+        if opts::multiprocess() {
             return Ok(OptionalIpcSender::OutOfProcess(try!(Deserialize::deserialize(
                             deserializer))))
         }
         let id: usize = try!(Deserialize::deserialize(deserializer));
-        let sender = (*IN_PROCESS_SENDERS.lock()
-                                         .unwrap()
-                                         .remove(&id)
-                                         .unwrap()
-                                         .downcast_ref::<Sender<T>>()
-                                         .unwrap()).clone();
-        Ok(OptionalIpcSender::InProcess(sender))
+        let sender = IN_PROCESS_SENDERS.lock().unwrap().remove(&id).unwrap();
+        Ok(OptionalIpcSender::InProcess(sender.to().unwrap()))
      }
 }
 
@@ -72,16 +80,91 @@ impl<T> Serialize for OptionalIpcSender<T> where T: Deserialize + Serialize + Se
                 let id = NEXT_SENDER_ID.fetch_add(1, Ordering::SeqCst);
                 IN_PROCESS_SENDERS.lock()
                                   .unwrap()
-                                  .insert(id, Box::new((*sender).clone()) as Box<Any + Send>);
+                                  .insert(id, OpaqueSender::new((*sender).clone()));
                 id.serialize(serializer)
             }
         }
     }
 }
 
+#[derive(Clone)]
+pub enum OptionalOpaqueIpcSender {
+    OutOfProcess(OpaqueIpcSender),
+    InProcess(OpaqueSender),
+}
+
+impl OptionalOpaqueIpcSender {
+    pub fn to<T>(self) -> OptionalIpcSender<T>
+                 where T: Deserialize + Serialize + Send + Any + 'static {
+        match self {
+            OptionalOpaqueIpcSender::OutOfProcess(ipc_sender) => {
+                OptionalIpcSender::OutOfProcess(ipc_sender.to())
+            }
+            OptionalOpaqueIpcSender::InProcess(sender) => {
+                OptionalIpcSender::InProcess(sender.to().unwrap())
+            }
+        }
+    }
+}
+
+impl Deserialize for OptionalOpaqueIpcSender {
+    fn deserialize<D>(deserializer: &mut D)
+                      -> Result<OptionalOpaqueIpcSender, D::Error> where D: Deserializer {
+        if opts::multiprocess() {
+            return Ok(OptionalOpaqueIpcSender::OutOfProcess(try!(Deserialize::deserialize(
+                            deserializer))))
+        }
+        let id: usize = try!(Deserialize::deserialize(deserializer));
+        let sender = IN_PROCESS_SENDERS.lock().unwrap().remove(&id).unwrap();
+        Ok(OptionalOpaqueIpcSender::InProcess(sender))
+     }
+}
+
+impl Serialize for OptionalOpaqueIpcSender {
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+        match *self {
+            OptionalOpaqueIpcSender::OutOfProcess(ref ipc_sender) => {
+                ipc_sender.serialize(serializer)
+            }
+            OptionalOpaqueIpcSender::InProcess(ref sender) => {
+                let id = NEXT_SENDER_ID.fetch_add(1, Ordering::SeqCst);
+                IN_PROCESS_SENDERS.lock().unwrap().insert(id, (*sender).clone());
+                id.serialize(serializer)
+            }
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct OpaqueSender {
+    sender: Sender<()>,
+    id: TypeId,
+}
+
+impl OpaqueSender {
+    fn new<T>(sender: Sender<T>) -> OpaqueSender where T: 'static + Reflect + Send {
+        unsafe {
+            OpaqueSender {
+                sender: mem::transmute::<_, Sender<()>>(sender),
+                id: TypeId::of::<T>(),
+            }
+        }
+    }
+
+    fn to<T>(self) -> Option<Sender<T>> where T: 'static + Reflect + Send {
+        unsafe {
+            if self.id != TypeId::of::<T>() {
+                None
+            } else {
+                Some(mem::transmute::<_, Sender<T>>(self.sender))
+            }
+        }
+    }
+}
+
 pub fn optional_ipc_channel<T>() -> (OptionalIpcSender<T>, Receiver<T>)
                                  where T: Deserialize + Serialize + Send + Any {
-    if opts::get().multiprocess {
+    if opts::multiprocess() {
         let (ipc_sender, ipc_receiver) = ipc::channel().unwrap();
         let receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_receiver);
         (OptionalIpcSender::OutOfProcess(ipc_sender), receiver)
diff --git a/servo/components/util/lib.rs b/servo/components/util/lib.rs
index 595a6b54e20e..82fcf7ab62b2 100644
--- a/servo/components/util/lib.rs
+++ b/servo/components/util/lib.rs
@@ -14,6 +14,7 @@
 #![feature(optin_builtin_traits)]
 #![cfg_attr(not(target_os = "android"), feature(path_ext))]
 #![feature(plugin)]
+#![feature(reflect_marker)]
 #![feature(slice_splits)]
 #![feature(step_by)]
 #![feature(step_trait)]
diff --git a/servo/components/util/opts.rs b/servo/components/util/opts.rs
index ce8c75cd045a..761568de42df 100644
--- a/servo/components/util/opts.rs
+++ b/servo/components/util/opts.rs
@@ -18,10 +18,11 @@ use std::fs::File;
 use std::io::{self, Read, Write};
 use std::path::Path;
 use std::process;
+use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
 use url::{self, Url};
 
 /// Global flags for Servo, currently set on the command line.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct Opts {
     pub is_running_problem_test: bool,
 
@@ -143,9 +144,12 @@ pub struct Opts {
     /// An optional string allowing the user agent to be set for testing.
     pub user_agent: String,
 
-    /// Whether to run in multiprocess mode.
+    /// Whether we're running in multiprocess mode.
     pub multiprocess: bool,
 
+    /// Whether we're running inside the sandbox.
+    pub sandbox: bool,
+
     /// Dumps the flow tree after a layout.
     pub dump_flow_tree: bool,
 
@@ -375,6 +379,13 @@ static FORCE_CPU_PAINTING: bool = true;
 #[cfg(not(target_os = "android"))]
 static FORCE_CPU_PAINTING: bool = false;
 
+static MULTIPROCESS: AtomicBool = ATOMIC_BOOL_INIT;
+
+#[inline]
+pub fn multiprocess() -> bool {
+    MULTIPROCESS.load(Ordering::Relaxed)
+}
+
 enum UserAgent {
     Desktop,
     Android,
@@ -460,6 +471,7 @@ pub fn default_opts() -> Opts {
         initial_window_size: Size2D::typed(800, 600),
         user_agent: default_user_agent_string(DEFAULT_USER_AGENT),
         multiprocess: false,
+        sandbox: false,
         dump_flow_tree: false,
         dump_display_list: false,
         dump_display_list_json: false,
@@ -479,7 +491,7 @@ pub fn default_opts() -> Opts {
     }
 }
 
-pub fn from_cmdline_args(args: &[String]) {
+pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
     let (app_name, args) = args.split_first().unwrap();
 
     let mut opts = Options::new();
@@ -509,11 +521,14 @@ pub fn from_cmdline_args(args: &[String]) {
                 "Set custom user agent string (or android / gonk / desktop for platform default)",
                 "NCSA Mosaic/1.0 (X11;SunOS 4.1.4 sun4m)");
     opts.optflag("M", "multiprocess", "Run in multiprocess mode");
+    opts.optflag("S", "sandbox", "Run in a sandbox if multiprocess");
     opts.optopt("Z", "debug",
                 "A comma-separated string of debug options. Pass help to show available options.", "");
     opts.optflag("h", "help", "Print this message");
     opts.optopt("", "resources-path", "Path to find static resources", "/home/servo/resources");
     opts.optflag("", "sniff-mime-types" , "Enable MIME sniffing");
+    opts.optopt("", "content-process" , "Run as a content process and connect to the given pipe",
+                "servo-ipc-channel.abcdefg");
     opts.optmulti("", "pref",
                   "A preference to set to enable", "dom.mozbrowser.enabled");
     opts.optflag("b", "no-native-titlebar", "Do not use native titlebar");
@@ -530,6 +545,13 @@ pub fn from_cmdline_args(args: &[String]) {
         process::exit(0);
     };
 
+    // If this is the content process, we'll receive the real options over IPC. So just fill in
+    // some dummy options for now.
+    if let Some(content_process) = opt_match.opt_str("content-process") {
+        MULTIPROCESS.store(true, Ordering::SeqCst);
+        return ArgumentParsingResult::ContentProcess(content_process);
+    }
+
     let debug_string = match opt_match.opt_str("Z") {
         Some(string) => string,
         None => String::new()
@@ -627,6 +649,10 @@ pub fn from_cmdline_args(args: &[String]) {
         }
     };
 
+    if opt_match.opt_present("M") {
+        MULTIPROCESS.store(true, Ordering::SeqCst)
+    }
+
     let user_agent = match opt_match.opt_str("u") {
         Some(ref ua) if ua == "android" => default_user_agent_string(UserAgent::Android),
         Some(ref ua) if ua == "gonk" => default_user_agent_string(UserAgent::Gonk),
@@ -675,6 +701,7 @@ pub fn from_cmdline_args(args: &[String]) {
         initial_window_size: initial_window_size,
         user_agent: user_agent,
         multiprocess: opt_match.opt_present("M"),
+        sandbox: opt_match.opt_present("S"),
         show_debug_borders: debug_options.show_compositor_borders,
         show_debug_fragment_borders: debug_options.show_fragment_borders,
         show_debug_parallel_paint: debug_options.show_parallel_paint,
@@ -704,6 +731,22 @@ pub fn from_cmdline_args(args: &[String]) {
     for pref in opt_match.opt_strs("pref").iter() {
         prefs::set_pref(pref, PrefValue::Boolean(true));
     }
+
+    ArgumentParsingResult::ChromeProcess
+}
+
+pub enum ArgumentParsingResult {
+    ChromeProcess,
+    ContentProcess(String),
+}
+
+static EXPERIMENTAL_ENABLED: AtomicBool = ATOMIC_BOOL_INIT;
+
+/// Turn on experimental features globally. Normally this is done
+/// during initialization by `set` or `from_cmdline_args`, but
+/// tests that require experimental features will also set it.
+pub fn set_experimental_enabled(new_value: bool) {
+    EXPERIMENTAL_ENABLED.store(new_value, Ordering::SeqCst);
 }
 
 // Make Opts available globally. This saves having to clone and pass
diff --git a/servo/components/util/str.rs b/servo/components/util/str.rs
index de3b5eb42b91..9978464ee0df 100644
--- a/servo/components/util/str.rs
+++ b/servo/components/util/str.rs
@@ -558,7 +558,7 @@ pub fn parse_legacy_color(mut input: &str) -> Result<RGBA, ()> {
 }
 
 
-#[derive(Clone, Eq, PartialEq, Hash, Debug)]
+#[derive(Clone, Eq, PartialEq, Hash, Debug, Deserialize, Serialize)]
 pub struct LowercaseString {
     inner: String,
 }
diff --git a/servo/components/util/task.rs b/servo/components/util/task.rs
index 2495bb8acd5d..c9b9463ed294 100644
--- a/servo/components/util/task.rs
+++ b/servo/components/util/task.rs
@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+use ipc_channel::ipc::IpcSender;
+use serde::Serialize;
 use std::borrow::ToOwned;
 use std::sync::mpsc::Sender;
 use std::thread;
@@ -15,15 +17,36 @@ pub fn spawn_named<F>(name: String, f: F)
     builder.spawn(f).unwrap();
 }
 
+/// An abstraction over `Sender<T>` and `IpcSender<T>`, for use in
+/// `spawn_named_with_send_on_failure`.
+pub trait SendOnFailure {
+    type Value;
+    fn send_on_failure(&mut self, value: Self::Value);
+}
+
+impl<T> SendOnFailure for Sender<T> where T: Send + 'static {
+    type Value = T;
+    fn send_on_failure(&mut self, value: T) {
+        self.send(value).unwrap();
+    }
+}
+
+impl<T> SendOnFailure for IpcSender<T> where T: Send + Serialize + 'static {
+    type Value = T;
+    fn send_on_failure(&mut self, value: T) {
+        self.send(value).unwrap();
+    }
+}
+
 /// Arrange to send a particular message to a channel if the task fails.
-pub fn spawn_named_with_send_on_failure<F, T>(name: String,
-                                              state: task_state::TaskState,
-                                              f: F,
-                                              msg: T,
-                                              dest: Sender<T>)
-    where F: FnOnce() + Send + 'static,
-          T: Send + 'static
-{
+pub fn spawn_named_with_send_on_failure<F, T, S>(name: String,
+                                                 state: task_state::TaskState,
+                                                 f: F,
+                                                 msg: T,
+                                                 mut dest: S)
+                                                 where F: FnOnce() + Send + 'static,
+                                                       T: Send + 'static,
+                                                       S: Send + SendOnFailure<Value=T> + 'static {
     let future_handle = thread::Builder::new().name(name.to_owned()).spawn(move || {
         task_state::initialize(state);
         f()
@@ -35,8 +58,9 @@ pub fn spawn_named_with_send_on_failure<F, T>(name: String,
             Ok(()) => (),
             Err(..) => {
                 debug!("{} failed, notifying constellation", name);
-                dest.send(msg).unwrap();
+                dest.send_on_failure(msg);
             }
         }
     }).unwrap();
 }
+
diff --git a/servo/components/webdriver_server/lib.rs b/servo/components/webdriver_server/lib.rs
index a899da65137e..2abdb5621148 100644
--- a/servo/components/webdriver_server/lib.rs
+++ b/servo/components/webdriver_server/lib.rs
@@ -28,7 +28,7 @@ use image::{DynamicImage, ImageFormat, RgbImage};
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use keys::keycodes_to_keys;
 use msg::constellation_msg::CompositorMsg as ConstellationMsg;
-use msg::constellation_msg::{ConstellationChan, FrameId, LoadData, PipelineId};
+use msg::constellation_msg::{FrameId, LoadData, PipelineId};
 use msg::constellation_msg::{NavigationDirection, PixelFormat, WebDriverCommandMsg};
 use msg::webdriver_msg::{LoadStatus, WebDriverFrameId, WebDriverJSError, WebDriverJSResult, WebDriverScriptCommand};
 use regex::Captures;
@@ -37,6 +37,7 @@ use rustc_serialize::json::{Json, ToJson};
 use std::borrow::ToOwned;
 use std::collections::BTreeMap;
 use std::net::SocketAddr;
+use std::sync::mpsc::Sender;
 use std::thread::{self, sleep_ms};
 use url::Url;
 use util::prefs::{get_pref, reset_all_prefs, reset_pref, set_pref, PrefValue};
@@ -57,7 +58,7 @@ fn extension_routes() -> Vec<(Method, &'static str, ServoExtensionRoute)> {
                 (Post, "/session/{sessionId}/servo/prefs/reset", ServoExtensionRoute::ResetPrefs)]
 }
 
-pub fn start_server(port: u16, constellation_chan: ConstellationChan<ConstellationMsg>) {
+pub fn start_server(port: u16, constellation_chan: Sender<ConstellationMsg>) {
     let handler = Handler::new(constellation_chan);
     spawn_named("WebdriverHttpServer".to_owned(), move || {
         server::start(SocketAddr::new("0.0.0.0".parse().unwrap(), port), handler,
@@ -72,7 +73,7 @@ struct WebDriverSession {
 
 struct Handler {
     session: Option<WebDriverSession>,
-    constellation_chan: ConstellationChan<ConstellationMsg>,
+    constellation_chan: Sender<ConstellationMsg>,
     script_timeout: u32,
     load_timeout: u32,
     implicit_wait_timeout: u32
@@ -208,7 +209,7 @@ impl WebDriverSession {
 }
 
 impl Handler {
-    pub fn new(constellation_chan: ConstellationChan<ConstellationMsg>) -> Handler {
+    pub fn new(constellation_chan: Sender<ConstellationMsg>) -> Handler {
         Handler {
             session: None,
             constellation_chan: constellation_chan,
@@ -267,8 +268,7 @@ impl Handler {
 
     fn pipeline(&self, frame_id: Option<FrameId>) -> Option<PipelineId> {
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
-        const_chan.send(ConstellationMsg::GetPipeline(frame_id, sender)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::GetPipeline(frame_id, sender)).unwrap();
 
 
         receiver.recv().unwrap()
@@ -307,9 +307,8 @@ impl Handler {
         let (sender, receiver) = ipc::channel().unwrap();
 
         let load_data = LoadData::new(url);
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd_msg = WebDriverCommandMsg::LoadUrl(pipeline_id, load_data, sender.clone());
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         self.wait_for_load(sender, receiver)
     }
@@ -337,10 +336,9 @@ impl Handler {
 
         let (sender, receiver) = ipc::channel().unwrap();
 
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id,
                                                          WebDriverScriptCommand::GetUrl(sender));
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         let url = receiver.recv().unwrap();
 
@@ -348,14 +346,12 @@ impl Handler {
     }
 
     fn handle_go_back(&self) -> WebDriverResult<WebDriverResponse> {
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
-        const_chan.send(ConstellationMsg::Navigate(None, NavigationDirection::Back)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::Navigate(None, NavigationDirection::Back)).unwrap();
         Ok(WebDriverResponse::Void)
     }
 
     fn handle_go_forward(&self) -> WebDriverResult<WebDriverResponse> {
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
-        const_chan.send(ConstellationMsg::Navigate(None, NavigationDirection::Forward)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::Navigate(None, NavigationDirection::Forward)).unwrap();
         Ok(WebDriverResponse::Void)
     }
 
@@ -364,9 +360,8 @@ impl Handler {
 
         let (sender, receiver) = ipc::channel().unwrap();
 
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd_msg = WebDriverCommandMsg::Refresh(pipeline_id, sender.clone());
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         self.wait_for_load(sender, receiver)
     }
@@ -375,10 +370,9 @@ impl Handler {
         let pipeline_id = try!(self.root_pipeline());
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id,
                                                          WebDriverScriptCommand::GetTitle(sender));
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         let value = receiver.recv().unwrap();
         Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json())))
     }
@@ -406,10 +400,9 @@ impl Handler {
         }
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::FindElementCSS(parameters.value.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         match receiver.recv().unwrap() {
             Ok(value) => {
                 let value_resp = value.map(|x| WebElement::new(x).to_json()).to_json();
@@ -448,16 +441,14 @@ impl Handler {
         let (sender, receiver) = ipc::channel().unwrap();
         let cmd = WebDriverScriptCommand::GetFrameId(frame_id, sender);
         {
-            let ConstellationChan(ref const_chan) = self.constellation_chan;
-            const_chan.send(ConstellationMsg::WebDriverCommand(
+            self.constellation_chan.send(ConstellationMsg::WebDriverCommand(
                 WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd))).unwrap();
         }
 
         let frame = match receiver.recv().unwrap() {
             Ok(Some(pipeline_id)) => {
                 let (sender, receiver) = ipc::channel().unwrap();
-                let ConstellationChan(ref const_chan) = self.constellation_chan;
-                const_chan.send(ConstellationMsg::GetFrame(pipeline_id, sender)).unwrap();
+                self.constellation_chan.send(ConstellationMsg::GetFrame(pipeline_id, sender)).unwrap();
                 receiver.recv().unwrap()
             },
             Ok(None) => None,
@@ -481,10 +472,9 @@ impl Handler {
         }
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::FindElementsCSS(parameters.value.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         match receiver.recv().unwrap() {
             Ok(value) => {
                 let resp_value: Vec<Json> = value.into_iter().map(
@@ -500,10 +490,9 @@ impl Handler {
         let pipeline_id = try!(self.frame_pipeline());
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::GetElementText(element.id.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         match receiver.recv().unwrap() {
             Ok(value) => Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json()))),
             Err(_) => Err(WebDriverError::new(ErrorStatus::StaleElementReference,
@@ -515,10 +504,9 @@ impl Handler {
         let pipeline_id = try!(self.frame_pipeline());
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::GetActiveElement(sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         let value = receiver.recv().unwrap().map(|x| WebElement::new(x).to_json());
         Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json())))
     }
@@ -527,10 +515,9 @@ impl Handler {
         let pipeline_id = try!(self.frame_pipeline());
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::GetElementTagName(element.id.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         match receiver.recv().unwrap() {
             Ok(value) => Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json()))),
             Err(_) => Err(WebDriverError::new(ErrorStatus::StaleElementReference,
@@ -542,10 +529,9 @@ impl Handler {
         let pipeline_id = try!(self.frame_pipeline());
 
         let (sender, receiver) = ipc::channel().unwrap();
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd = WebDriverScriptCommand::GetElementAttribute(element.id.clone(), name.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
         match receiver.recv().unwrap() {
             Ok(value) => Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json()))),
             Err(_) => Err(WebDriverError::new(ErrorStatus::StaleElementReference,
@@ -601,9 +587,8 @@ impl Handler {
                       -> WebDriverResult<WebDriverResponse> {
         let pipeline_id = try!(self.frame_pipeline());
 
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, command);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         match receiver.recv().unwrap() {
             Ok(value) => Ok(WebDriverResponse::Generic(ValueResponse::new(value.to_json()))),
@@ -618,12 +603,11 @@ impl Handler {
                                 keys: &SendKeysParameters) -> WebDriverResult<WebDriverResponse> {
         let pipeline_id = try!(self.frame_pipeline());
 
-        let ConstellationChan(ref const_chan) = self.constellation_chan;
         let (sender, receiver) = ipc::channel().unwrap();
 
         let cmd = WebDriverScriptCommand::FocusElement(element.id.clone(), sender);
         let cmd_msg = WebDriverCommandMsg::ScriptCommand(pipeline_id, cmd);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         // TODO: distinguish the not found and not focusable cases
         try!(receiver.recv().unwrap().or_else(|_| Err(WebDriverError::new(
@@ -633,7 +617,7 @@ impl Handler {
             Err(WebDriverError::new(ErrorStatus::UnsupportedOperation, "Failed to convert keycodes"))));
 
         let cmd_msg = WebDriverCommandMsg::SendKeys(pipeline_id, keys);
-        const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+        self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
         Ok(WebDriverResponse::Void)
     }
@@ -647,9 +631,8 @@ impl Handler {
 
         for _ in 0..iterations {
             let (sender, receiver) = ipc::channel().unwrap();
-            let ConstellationChan(ref const_chan) = self.constellation_chan;
             let cmd_msg = WebDriverCommandMsg::TakeScreenshot(pipeline_id, sender);
-            const_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
+            self.constellation_chan.send(ConstellationMsg::WebDriverCommand(cmd_msg)).unwrap();
 
             if let Some(x) = receiver.recv().unwrap() {
                 img = Some(x);
diff --git a/servo/ports/cef/Cargo.lock b/servo/ports/cef/Cargo.lock
index 4d5970755c44..7178aed16ca3 100644
--- a/servo/ports/cef/Cargo.lock
+++ b/servo/ports/cef/Cargo.lock
@@ -253,6 +253,7 @@ dependencies = [
  "core-text 0.1.0 (git+https://github.com/servo/core-text-rs)",
  "devtools_traits 0.0.1",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gfx_traits 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -260,6 +261,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout_traits 0.0.1",
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
@@ -268,6 +270,8 @@ dependencies = [
  "plugins 0.0.1",
  "profile_traits 0.0.1",
  "script_traits 0.0.1",
+ "serde 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -559,6 +563,16 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "gaol"
+version = "0.0.1"
+source = "git+https://github.com/pcwalton/gaol#71865ff8a1824cbc1cbee4d388d56c5ba1b5ffc2"
+dependencies = [
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "gcc"
 version = "0.3.16"
@@ -1555,9 +1569,11 @@ dependencies = [
  "devtools_traits 0.0.1",
  "env_logger 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "glutin_app 0.0.1",
+ "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout 0.0.1",
  "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/servo/ports/gonk/Cargo.lock b/servo/ports/gonk/Cargo.lock
index 402e376b86e4..f94e3e5ccc15 100644
--- a/servo/ports/gonk/Cargo.lock
+++ b/servo/ports/gonk/Cargo.lock
@@ -245,6 +245,7 @@ dependencies = [
  "core-text 0.1.0 (git+https://github.com/servo/core-text-rs)",
  "devtools_traits 0.0.1",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gfx_traits 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -252,6 +253,7 @@ dependencies = [
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout_traits 0.0.1",
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
@@ -260,6 +262,8 @@ dependencies = [
  "plugins 0.0.1",
  "profile_traits 0.0.1",
  "script_traits 0.0.1",
+ "serde 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -561,6 +565,16 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "gaol"
+version = "0.0.1"
+source = "git+https://github.com/pcwalton/gaol#71865ff8a1824cbc1cbee4d388d56c5ba1b5ffc2"
+dependencies = [
+ "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "gcc"
 version = "0.3.16"
@@ -1535,8 +1549,10 @@ dependencies = [
  "devtools_traits 0.0.1",
  "env_logger 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gaol 0.0.1 (git+https://github.com/pcwalton/gaol)",
  "gfx 0.0.1",
  "gleam 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "layers 0.1.0 (git+https://github.com/servo/rust-layers)",
  "layout 0.0.1",
  "libc 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",