diff --git a/components/script/dom/bindings/refcounted.rs b/components/script/dom/bindings/refcounted.rs
index 1be8a369d8f..4da753cb833 100644
--- a/components/script/dom/bindings/refcounted.rs
+++ b/components/script/dom/bindings/refcounted.rs
@@ -32,7 +32,6 @@ use dom::promise::Promise;
 use js::jsapi::JSAutoCompartment;
 use js::jsapi::JSTracer;
 use libc;
-use script_thread::Task;
 use std::cell::RefCell;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::collections::hash_map::HashMap;
@@ -41,6 +40,7 @@ use std::marker::PhantomData;
 use std::os;
 use std::rc::Rc;
 use std::sync::{Arc, Weak};
+use task::Task;
 
 
 #[allow(missing_docs)]  // FIXME
diff --git a/components/script/dom/bluetooth.rs b/components/script/dom/bluetooth.rs
index 35e6fdde3b1..2cd557d52b8 100644
--- a/components/script/dom/bluetooth.rs
+++ b/components/script/dom/bluetooth.rs
@@ -35,12 +35,12 @@ use ipc_channel::router::ROUTER;
 use js::conversions::ConversionResult;
 use js::jsapi::{JSAutoCompartment, JSContext, JSObject};
 use js::jsval::{ObjectValue, UndefinedValue};
-use script_thread::Task;
 use std::cell::Ref;
 use std::collections::HashMap;
 use std::rc::Rc;
 use std::str::FromStr;
 use std::sync::{Arc, Mutex};
+use task::Task;
 
 const KEY_CONVERSION_ERROR: &'static str = "This `manufacturerData` key can not be parsed as unsigned short:";
 const FILTER_EMPTY_ERROR: &'static str = "'filters' member, if present, must be nonempty to find any devices.";
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index e0c5380cc59..90853a28e7f 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -113,7 +113,7 @@ use net_traits::response::HttpsState;
 use num_traits::ToPrimitive;
 use script_layout_interface::message::{Msg, ReflowQueryType};
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use script_thread::{MainThreadScriptMsg, ScriptThread, Task};
+use script_thread::{MainThreadScriptMsg, ScriptThread};
 use script_traits::{AnimationState, CompositorEvent, DocumentActivity};
 use script_traits::{MouseButton, MouseEventType, MozBrowserEvent};
 use script_traits::{MsDuration, ScriptMsg, TouchpadPressurePhase};
@@ -142,6 +142,7 @@ use style::shared_lock::{SharedRwLock as StyleSharedRwLock, SharedRwLockReadGuar
 use style::str::{HTML_SPACE_CHARACTERS, split_html_space_chars, str_join};
 use style::stylesheet_set::StylesheetSet;
 use style::stylesheets::{Stylesheet, StylesheetContents, Origin, OriginSet};
+use task::Task;
 use task_source::TaskSource;
 use time;
 use timers::OneshotTimerCallback;
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index f6322c65960..56fbcc0fcaf 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -87,7 +87,7 @@ use js::jsval::JSVal;
 use net_traits::request::CorsSettings;
 use ref_filter_map::ref_filter_map;
 use script_layout_interface::message::ReflowQueryType;
-use script_thread::{ScriptThread, Task};
+use script_thread::ScriptThread;
 use selectors::attr::{AttrSelectorOperation, NamespaceConstraint, CaseSensitivity};
 use selectors::matching::{ElementSelectorFlags, LocalMatchingContext, MatchingContext, MatchingMode};
 use selectors::matching::{HAS_EDGE_CHILD_SELECTOR, HAS_SLOW_SELECTOR, HAS_SLOW_SELECTOR_LATER_SIBLINGS};
@@ -119,6 +119,7 @@ use style::thread_state;
 use style::values::{CSSFloat, Either};
 use style::values::{specified, computed};
 use stylesheet_loader::StylesheetOwner;
+use task::Task;
 
 // TODO: Update focus state when the top-level browsing context gains or loses system focus,
 // and when the element enters or leaves a browsing context container.
diff --git a/components/script/dom/event.rs b/components/script/dom/event.rs
index fb6bf9c3b61..f5143ec72c4 100644
--- a/components/script/dom/event.rs
+++ b/components/script/dom/event.rs
@@ -20,10 +20,10 @@ use dom::node::Node;
 use dom::virtualmethods::vtable_for;
 use dom::window::Window;
 use dom_struct::dom_struct;
-use script_thread::Task;
 use servo_atoms::Atom;
 use std::cell::Cell;
 use std::default::Default;
+use task::Task;
 use time;
 
 #[dom_struct]
diff --git a/components/script/dom/eventsource.rs b/components/script/dom/eventsource.rs
index 2bd5f32261e..438200e3bab 100644
--- a/components/script/dom/eventsource.rs
+++ b/components/script/dom/eventsource.rs
@@ -27,13 +27,13 @@ use net_traits::{CoreResourceMsg, FetchMetadata, FetchResponseMsg, FetchResponse
 use net_traits::request::{CacheMode, CorsSettings, CredentialsMode};
 use net_traits::request::{RequestInit, RequestMode};
 use network_listener::{NetworkListener, PreInvoke};
-use script_thread::Task;
 use servo_atoms::Atom;
 use servo_url::ServoUrl;
 use std::cell::Cell;
 use std::mem;
 use std::str::{Chars, FromStr};
 use std::sync::{Arc, Mutex};
+use task::Task;
 use task_source::TaskSource;
 use timers::OneshotTimerCallback;
 use utf8;
diff --git a/components/script/dom/filereader.rs b/components/script/dom/filereader.rs
index d954e1431ef..b2f5b1ca36f 100644
--- a/components/script/dom/filereader.rs
+++ b/components/script/dom/filereader.rs
@@ -29,12 +29,12 @@ use js::jsapi::JSAutoCompartment;
 use js::jsapi::JSContext;
 use js::jsval::{self, JSVal};
 use js::typedarray::{ArrayBuffer, CreateWith};
-use script_thread::TaskCanceller;
 use servo_atoms::Atom;
 use std::cell::Cell;
 use std::ptr;
 use std::sync::Arc;
 use std::thread;
+use task::TaskCanceller;
 use task_source::TaskSource;
 use task_source::file_reading::{FileReadingTask, FileReadingTaskSource};
 
diff --git a/components/script/dom/globalscope.rs b/components/script/dom/globalscope.rs
index e661e315ea4..529b1791d59 100644
--- a/components/script/dom/globalscope.rs
+++ b/components/script/dom/globalscope.rs
@@ -38,7 +38,7 @@ use msg::constellation_msg::PipelineId;
 use net_traits::{CoreResourceThread, ResourceThreads, IpcSend};
 use profile_traits::{mem, time};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort};
-use script_thread::{MainThreadScriptChan, ScriptThread, TaskCanceller};
+use script_thread::{MainThreadScriptChan, ScriptThread};
 use script_traits::{MsDuration, ScriptToConstellationChan, TimerEvent};
 use script_traits::{TimerEventId, TimerSchedulerMsg, TimerSource};
 use servo_url::{MutableOrigin, ServoUrl};
@@ -47,6 +47,7 @@ use std::collections::HashMap;
 use std::collections::hash_map::Entry;
 use std::ffi::CString;
 use std::rc::Rc;
+use task::TaskCanceller;
 use task_source::file_reading::FileReadingTaskSource;
 use task_source::networking::NetworkingTaskSource;
 use task_source::performance_timeline::PerformanceTimelineTaskSource;
diff --git a/components/script/dom/htmldetailselement.rs b/components/script/dom/htmldetailselement.rs
index 4f4087b4c38..8cd5133dca7 100644
--- a/components/script/dom/htmldetailselement.rs
+++ b/components/script/dom/htmldetailselement.rs
@@ -16,8 +16,8 @@ use dom::node::{Node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
 use dom_struct::dom_struct;
 use html5ever::{LocalName, Prefix};
-use script_thread::Task;
 use std::cell::Cell;
+use task::Task;
 use task_source::TaskSource;
 
 #[dom_struct]
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 43771b17890..ca14df723b8 100755
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -49,7 +49,7 @@ use html5ever::{LocalName, Prefix};
 use hyper::header::{Charset, ContentDisposition, ContentType, DispositionParam, DispositionType};
 use hyper::method::Method;
 use msg::constellation_msg::PipelineId;
-use script_thread::{MainThreadScriptMsg, Task};
+use script_thread::MainThreadScriptMsg;
 use script_traits::LoadData;
 use servo_rand::random;
 use std::borrow::ToOwned;
@@ -57,6 +57,7 @@ use std::cell::Cell;
 use std::sync::mpsc::Sender;
 use style::attr::AttrValue;
 use style::str::split_html_space_chars;
+use task::Task;
 use task_source::TaskSource;
 
 #[derive(Clone, Copy, HeapSizeOf, JSTraceable, PartialEq)]
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index fa6639ad422..0452c40d2f9 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -43,7 +43,7 @@ use js::jsval::{NullValue, UndefinedValue};
 use msg::constellation_msg::{FrameType, BrowsingContextId, PipelineId, TopLevelBrowsingContextId, TraversalDirection};
 use net_traits::response::HttpsState;
 use script_layout_interface::message::ReflowQueryType;
-use script_thread::{ScriptThread, Task};
+use script_thread::ScriptThread;
 use script_traits::{IFrameLoadInfo, IFrameLoadInfoWithData, JsEvalResult, LoadData, UpdatePipelineIdReason};
 use script_traits::{MozBrowserEvent, NewLayoutInfo, ScriptMsg};
 use script_traits::IFrameSandboxState::{IFrameSandboxed, IFrameUnsandboxed};
@@ -54,6 +54,7 @@ use servo_url::ServoUrl;
 use std::cell::Cell;
 use style::attr::{AttrValue, LengthOrPercentageOrAuto};
 use style::context::ReflowGoal;
+use task::Task;
 use task_source::TaskSource;
 
 bitflags! {
diff --git a/components/script/dom/htmlimageelement.rs b/components/script/dom/htmlimageelement.rs
index 23348c9d263..9967728e745 100644
--- a/components/script/dom/htmlimageelement.rs
+++ b/components/script/dom/htmlimageelement.rs
@@ -48,7 +48,7 @@ use net_traits::image_cache::UsePlaceholder;
 use net_traits::request::{RequestInit, Type as RequestType};
 use network_listener::{NetworkListener, PreInvoke};
 use num_traits::ToPrimitive;
-use script_thread::{ScriptThread, Task};
+use script_thread::ScriptThread;
 use servo_url::ServoUrl;
 use servo_url::origin::ImmutableOrigin;
 use std::cell::{Cell, RefMut};
@@ -56,6 +56,7 @@ use std::default::Default;
 use std::i32;
 use std::sync::{Arc, Mutex};
 use style::attr::{AttrValue, LengthOrPercentageOrAuto};
+use task::Task;
 use task_source::TaskSource;
 
 #[derive(Clone, Copy, HeapSizeOf, JSTraceable)]
diff --git a/components/script/dom/htmlmediaelement.rs b/components/script/dom/htmlmediaelement.rs
index 0f4549b0809..f307dc2e733 100644
--- a/components/script/dom/htmlmediaelement.rs
+++ b/components/script/dom/htmlmediaelement.rs
@@ -35,10 +35,11 @@ use microtask::{Microtask, MicrotaskRunnable};
 use net_traits::{FetchResponseListener, FetchMetadata, Metadata, NetworkError};
 use net_traits::request::{CredentialsMode, Destination, RequestInit, Type as RequestType};
 use network_listener::{NetworkListener, PreInvoke};
-use script_thread::{ScriptThread, Task};
+use script_thread::ScriptThread;
 use servo_url::ServoUrl;
 use std::cell::Cell;
 use std::sync::{Arc, Mutex};
+use task::Task;
 use task_source::TaskSource;
 use time::{self, Timespec, Duration};
 
diff --git a/components/script/dom/serviceworker.rs b/components/script/dom/serviceworker.rs
index add6279e0a0..74169428453 100644
--- a/components/script/dom/serviceworker.rs
+++ b/components/script/dom/serviceworker.rs
@@ -16,10 +16,10 @@ use dom::eventtarget::EventTarget;
 use dom::globalscope::GlobalScope;
 use dom_struct::dom_struct;
 use js::jsapi::{HandleValue, JSContext};
-use script_thread::Task;
 use script_traits::{ScriptMsg, DOMMessage};
 use servo_url::ServoUrl;
 use std::cell::Cell;
+use task::Task;
 
 pub type TrustedServiceWorkerAddress = Trusted<ServiceWorker>;
 
diff --git a/components/script/dom/storage.rs b/components/script/dom/storage.rs
index 65c21bc6706..fdd2ae4c504 100644
--- a/components/script/dom/storage.rs
+++ b/components/script/dom/storage.rs
@@ -17,9 +17,9 @@ use dom_struct::dom_struct;
 use ipc_channel::ipc::{self, IpcSender};
 use net_traits::IpcSend;
 use net_traits::storage_thread::{StorageThreadMsg, StorageType};
-use script_thread::Task;
 use script_traits::ScriptMsg;
 use servo_url::ServoUrl;
+use task::Task;
 use task_source::TaskSource;
 
 #[dom_struct]
diff --git a/components/script/dom/vrdisplay.rs b/components/script/dom/vrdisplay.rs
index 9bc40bd5a82..2b2ab80f2e5 100644
--- a/components/script/dom/vrdisplay.rs
+++ b/components/script/dom/vrdisplay.rs
@@ -36,12 +36,12 @@ use ipc_channel::ipc::{self, IpcSender};
 use js::jsapi::JSContext;
 use script_runtime::CommonScriptMsg;
 use script_runtime::ScriptThreadEventCategory::WebVREvent;
-use script_thread::Task;
 use std::cell::Cell;
 use std::mem;
 use std::rc::Rc;
 use std::sync::mpsc;
 use std::thread;
+use task::Task;
 use webvr_traits::{WebVRDisplayData, WebVRDisplayEvent, WebVRFrameData, WebVRLayer, WebVRMsg};
 
 #[dom_struct]
diff --git a/components/script/dom/websocket.rs b/components/script/dom/websocket.rs
index a390381b924..52b2dcc85d6 100644
--- a/components/script/dom/websocket.rs
+++ b/components/script/dom/websocket.rs
@@ -31,13 +31,13 @@ use net_traits::CoreResourceMsg::WebsocketConnect;
 use net_traits::MessageData;
 use script_runtime::CommonScriptMsg;
 use script_runtime::ScriptThreadEventCategory::WebSocketEvent;
-use script_thread::{Task, TaskCanceller};
 use servo_url::ServoUrl;
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
 use std::cell::Cell;
 use std::ptr;
 use std::thread;
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 use task_source::networking::NetworkingTaskSource;
 
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 3b555ca7c4c..7492962e682 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -76,8 +76,8 @@ use script_layout_interface::rpc::{ContentBoxResponse, ContentBoxesResponse, Lay
 use script_layout_interface::rpc::{MarginStyleResponse, NodeScrollRootIdResponse};
 use script_layout_interface::rpc::{ResolvedStyleResponse, TextIndexResponse};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptThreadEventCategory};
-use script_thread::{ImageCacheMsg, MainThreadScriptChan, MainThreadScriptMsg, Task};
-use script_thread::{ScriptThread, SendableMainThreadScriptChan, TaskCanceller};
+use script_thread::{ImageCacheMsg, MainThreadScriptChan, MainThreadScriptMsg};
+use script_thread::{ScriptThread, SendableMainThreadScriptChan};
 use script_traits::{ConstellationControlMsg, DocumentState, LoadData, MozBrowserEvent};
 use script_traits::{ScriptToConstellationChan, ScriptMsg, ScrollState, TimerEvent, TimerEventId};
 use script_traits::{TimerSchedulerMsg, UntrustedNodeAddress, WindowSizeData, WindowSizeType};
@@ -111,6 +111,7 @@ use style::selector_parser::PseudoElement;
 use style::str::HTML_SPACE_CHARACTERS;
 use style::stylesheets::CssRuleType;
 use style_traits::PARSING_MODE_DEFAULT;
+use task::{Task, TaskCanceller};
 use task_source::dom_manipulation::DOMManipulationTaskSource;
 use task_source::file_reading::FileReadingTaskSource;
 use task_source::history_traversal::HistoryTraversalTaskSource;
diff --git a/components/script/dom/worker.rs b/components/script/dom/worker.rs
index 498cae4b0f4..70efc86606a 100644
--- a/components/script/dom/worker.rs
+++ b/components/script/dom/worker.rs
@@ -25,12 +25,12 @@ use dom_struct::dom_struct;
 use ipc_channel::ipc;
 use js::jsapi::{HandleValue, JSAutoCompartment, JSContext, NullHandleValue};
 use js::jsval::UndefinedValue;
-use script_thread::Task;
 use script_traits::WorkerScriptLoadOrigin;
 use std::cell::Cell;
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{Sender, channel};
+use task::Task;
 
 pub type TrustedWorkerAddress = Trusted<Worker>;
 
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index c26fcc63fdb..57017f5cd55 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -33,7 +33,6 @@ use js::rust::Runtime;
 use net_traits::{IpcSend, load_whole_resource};
 use net_traits::request::{CredentialsMode, Destination, RequestInit as NetRequestInit, Type as RequestType};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, get_reports};
-use script_thread::TaskCanceller;
 use script_traits::{TimerEvent, TimerEventId};
 use script_traits::WorkerGlobalScopeInit;
 use servo_url::{MutableOrigin, ServoUrl};
@@ -42,6 +41,7 @@ use std::rc::Rc;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::Receiver;
+use task::TaskCanceller;
 use task_source::file_reading::FileReadingTaskSource;
 use task_source::networking::NetworkingTaskSource;
 use task_source::performance_timeline::PerformanceTimelineTaskSource;
diff --git a/components/script/dom/worklet.rs b/components/script/dom/worklet.rs
index 9bfec3c78cb..b55f9d328a0 100644
--- a/components/script/dom/worklet.rs
+++ b/components/script/dom/worklet.rs
@@ -51,7 +51,7 @@ use script_runtime::CommonScriptMsg;
 use script_runtime::ScriptThreadEventCategory;
 use script_runtime::StackRootTLS;
 use script_runtime::new_rt_and_cx;
-use script_thread::{MainThreadScriptMsg, ScriptThread, Task};
+use script_thread::{MainThreadScriptMsg, ScriptThread};
 use servo_rand;
 use servo_url::ImmutableOrigin;
 use servo_url::ServoUrl;
@@ -69,6 +69,7 @@ use std::thread;
 use style::thread_state;
 use swapper::Swapper;
 use swapper::swapper;
+use task::Task;
 use uuid::Uuid;
 
 // Magic numbers
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 5ba671440bd..b015a5407b0 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -123,6 +123,7 @@ pub mod script_thread;
 mod serviceworker_manager;
 mod serviceworkerjob;
 mod stylesheet_loader;
+mod task;
 mod task_source;
 pub mod test;
 pub mod textinput;
diff --git a/components/script/network_listener.rs b/components/script/network_listener.rs
index aa167ecdfca..8b291128065 100644
--- a/components/script/network_listener.rs
+++ b/components/script/network_listener.rs
@@ -3,8 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use net_traits::{Action, FetchResponseListener, FetchResponseMsg};
-use script_thread::{Task, TaskCanceller};
 use std::sync::{Arc, Mutex};
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 use task_source::networking::NetworkingTaskSource;
 
diff --git a/components/script/script_runtime.rs b/components/script/script_runtime.rs
index b12649668e5..270dd0cdafe 100644
--- a/components/script/script_runtime.rs
+++ b/components/script/script_runtime.rs
@@ -23,7 +23,7 @@ use js::panic::wrap_panic;
 use js::rust::Runtime;
 use microtask::{EnqueuedPromiseCallback, Microtask};
 use profile_traits::mem::{Report, ReportKind, ReportsChan};
-use script_thread::{STACK_ROOTS, Task, trace_thread};
+use script_thread::{STACK_ROOTS, trace_thread};
 use servo_config::opts;
 use servo_config::prefs::PREFS;
 use std::cell::Cell;
@@ -35,6 +35,7 @@ use std::os::raw::c_void;
 use std::panic::AssertUnwindSafe;
 use std::ptr;
 use style::thread_state;
+use task::Task;
 use time::{Tm, now};
 
 /// Common messages used to control the event loops in both the script and the worker
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 21989316864..56f47cfdbef 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -105,15 +105,12 @@ use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
 use std::cell::Cell;
 use std::collections::{hash_map, HashMap, HashSet};
 use std::default::Default;
-use std::fmt;
-use std::intrinsics;
 use std::ops::Deref;
 use std::option::Option;
 use std::ptr;
 use std::rc::Rc;
 use std::result::Result;
 use std::sync::Arc;
-use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{Receiver, Select, Sender, channel};
 use std::thread;
 use style::context::ReflowGoal;
@@ -206,62 +203,6 @@ impl InProgressLoad {
     }
 }
 
-/// Encapsulated state required to create cancellable tasks from non-script threads.
-pub struct TaskCanceller {
-    pub cancelled: Option<Arc<AtomicBool>>,
-}
-
-impl TaskCanceller {
-    pub fn wrap_task<T>(&self, task: Box<T>) -> Box<Task + Send>
-    where
-        T: Send + Task + 'static,
-    {
-        box CancellableTask {
-            cancelled: self.cancelled.clone(),
-            inner: task,
-        }
-    }
-}
-
-/// A task that can be discarded by toggling a shared flag.
-pub struct CancellableTask<T: Send + Task> {
-    cancelled: Option<Arc<AtomicBool>>,
-    inner: Box<T>,
-}
-
-impl<T> CancellableTask<T>
-where
-    T: Send + Task,
-{
-    fn is_cancelled(&self) -> bool {
-        self.cancelled.as_ref().map_or(false, |cancelled| {
-            cancelled.load(Ordering::SeqCst)
-        })
-    }
-}
-
-impl<T> Task for CancellableTask<T>
-where
-    T: Send + Task,
-{
-    fn run(self: Box<Self>) {
-        if !self.is_cancelled() {
-            self.inner.run()
-        }
-    }
-}
-
-pub trait Task {
-    fn name(&self) -> &'static str { unsafe { intrinsics::type_name::<Self>() } }
-    fn run(self: Box<Self>);
-}
-
-impl fmt::Debug for Task + Send {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt.debug_tuple(self.name()).field(&format_args!("...")).finish()
-    }
-}
-
 #[derive(Debug)]
 enum MixedMessage {
     FromConstellation(ConstellationControlMsg),
diff --git a/components/script/serviceworkerjob.rs b/components/script/serviceworkerjob.rs
index db457dc394a..fef1d02e4da 100644
--- a/components/script/serviceworkerjob.rs
+++ b/components/script/serviceworkerjob.rs
@@ -18,11 +18,12 @@ use dom::promise::Promise;
 use dom::serviceworkerregistration::ServiceWorkerRegistration;
 use dom::urlhelper::UrlHelper;
 use js::jsapi::JSAutoCompartment;
-use script_thread::{ScriptThread, Task};
+use script_thread::ScriptThread;
 use servo_url::ServoUrl;
 use std::cmp::PartialEq;
 use std::collections::HashMap;
 use std::rc::Rc;
+use task::Task;
 use task_source::TaskSource;
 use task_source::dom_manipulation::DOMManipulationTaskSource;
 
diff --git a/components/script/task.rs b/components/script/task.rs
new file mode 100644
index 00000000000..55c8f37aca4
--- /dev/null
+++ b/components/script/task.rs
@@ -0,0 +1,70 @@
+/* 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/. */
+
+//! Machinery for [tasks](https://html.spec.whatwg.org/multipage/#concept-task).
+
+use std::fmt;
+use std::intrinsics;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+
+/// A task that can be run. The name method is for profiling purposes.
+pub trait Task {
+    #[allow(unsafe_code)]
+    fn name(&self) -> &'static str { unsafe { intrinsics::type_name::<Self>() } }
+    fn run(self: Box<Self>);
+}
+
+impl fmt::Debug for Task + Send {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_tuple(self.name()).field(&format_args!("...")).finish()
+    }
+}
+
+/// Encapsulated state required to create cancellable tasks from non-script threads.
+pub struct TaskCanceller {
+    pub cancelled: Option<Arc<AtomicBool>>,
+}
+
+impl TaskCanceller {
+    /// Returns a wrapped `task` that will be cancelled if the `TaskCanceller`
+    /// says so.
+    pub fn wrap_task<T>(&self, task: Box<T>) -> Box<Task + Send>
+    where
+        T: Send + Task + 'static,
+    {
+        box CancellableTask {
+            cancelled: self.cancelled.clone(),
+            inner: task,
+        }
+    }
+}
+
+/// A task that can be cancelled by toggling a shared flag.
+pub struct CancellableTask<T: Send + Task> {
+    cancelled: Option<Arc<AtomicBool>>,
+    inner: Box<T>,
+}
+
+impl<T> CancellableTask<T>
+where
+    T: Send + Task,
+{
+    fn is_cancelled(&self) -> bool {
+        self.cancelled.as_ref().map_or(false, |cancelled| {
+            cancelled.load(Ordering::SeqCst)
+        })
+    }
+}
+
+impl<T> Task for CancellableTask<T>
+where
+    T: Send + Task,
+{
+    fn run(self: Box<Self>) {
+        if !self.is_cancelled() {
+            self.inner.run()
+        }
+    }
+}
diff --git a/components/script/task_source/dom_manipulation.rs b/components/script/task_source/dom_manipulation.rs
index f7b7a6577f8..93cdfde95f4 100644
--- a/components/script/task_source/dom_manipulation.rs
+++ b/components/script/task_source/dom_manipulation.rs
@@ -8,11 +8,12 @@ use dom::event::{EventBubbles, EventCancelable, EventTask, SimpleEventTask};
 use dom::eventtarget::EventTarget;
 use dom::window::Window;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use script_thread::{MainThreadScriptMsg, Task, TaskCanceller};
+use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
 use std::fmt;
 use std::result::Result;
 use std::sync::mpsc::Sender;
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 
 #[derive(Clone, JSTraceable)]
diff --git a/components/script/task_source/file_reading.rs b/components/script/task_source/file_reading.rs
index dc9a6a751dd..1d44a4087d6 100644
--- a/components/script/task_source/file_reading.rs
+++ b/components/script/task_source/file_reading.rs
@@ -5,8 +5,8 @@
 use dom::domexception::DOMErrorName;
 use dom::filereader::{FileReader, TrustedFileReader, GenerationId, ReadMetaData};
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory, ScriptChan};
-use script_thread::{Task, TaskCanceller};
 use std::sync::Arc;
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 
 #[derive(JSTraceable)]
diff --git a/components/script/task_source/mod.rs b/components/script/task_source/mod.rs
index 3dbb753883e..40b3c2f3261 100644
--- a/components/script/task_source/mod.rs
+++ b/components/script/task_source/mod.rs
@@ -10,8 +10,8 @@ pub mod performance_timeline;
 pub mod user_interaction;
 
 use dom::globalscope::GlobalScope;
-use script_thread::{Task, TaskCanceller};
 use std::result::Result;
+use task::{Task, TaskCanceller};
 
 pub trait TaskSource {
     fn queue_with_canceller<T>(
diff --git a/components/script/task_source/networking.rs b/components/script/task_source/networking.rs
index 56c583d775f..5d339037729 100644
--- a/components/script/task_source/networking.rs
+++ b/components/script/task_source/networking.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
-use script_thread::{Task, TaskCanceller};
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 
 #[derive(JSTraceable)]
diff --git a/components/script/task_source/performance_timeline.rs b/components/script/task_source/performance_timeline.rs
index db80789a206..938566b7a8f 100644
--- a/components/script/task_source/performance_timeline.rs
+++ b/components/script/task_source/performance_timeline.rs
@@ -10,9 +10,9 @@ use dom::bindings::refcounted::Trusted;
 use dom::globalscope::GlobalScope;
 use dom::performance::Performance;
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
-use script_thread::{Task, TaskCanceller};
 use std::fmt;
 use std::result::Result;
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 
 pub struct NotifyPerformanceObserverTask {
diff --git a/components/script/task_source/user_interaction.rs b/components/script/task_source/user_interaction.rs
index 3e84e0fb19a..8b36a61e9d0 100644
--- a/components/script/task_source/user_interaction.rs
+++ b/components/script/task_source/user_interaction.rs
@@ -8,11 +8,12 @@ use dom::event::{EventBubbles, EventCancelable, EventTask};
 use dom::eventtarget::EventTarget;
 use dom::window::Window;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use script_thread::{MainThreadScriptMsg, Task, TaskCanceller};
+use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
 use std::fmt;
 use std::result::Result;
 use std::sync::mpsc::Sender;
+use task::{Task, TaskCanceller};
 use task_source::TaskSource;
 
 #[derive(Clone, JSTraceable)]