script: Refactor channels in ScriptThread into receivers and senders (#34776)

Create two new data structures in the `script` crate to hold senders and
receiver:

- `ScriptThreadSenders`: holds all outgoing channels from the
  `ScriptThread` including a channel to the `ScriptThread` itself. The
  ultimate goal with this is to reduce duplication by giving a boxed
  version of this this to `Window`s.
- `ScriptThradReceivers`: holds all incoming channels to the
  `ScriptThread`. This isn't cloenable like the senders. This is used to
  abstract away `recv()` and `try_recv()` methods used to make the
  `ScriptThread` event loop easier to read.

In addition:

- The many duplicated `ScriptThread` self-senders for the `TaskManager`
  have been removed and, in general, a lot of boilerplate is removed as
  well.
- Visibilty of all methods affected by this change is changed to
  `pub(crate)` in order to take advantage of dead code detection. Some
  dead code produced from macros is removed.
- Some conversion code is refactord into implementations of the `From`
  trait.
- The names of channels uses a standard "sender" and "receiver" naming
  as well as trying to be descriptive of where they go in `ScriptThread`
  as well as `InitialScriptState`

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/task_source/dom_manipulation.rs

@@ -22,7 +22,7 @@ pub struct DOMManipulationTaskSource(pub Box<dyn ScriptChan + Send>, #[no_trace]
 
 impl Clone for DOMManipulationTaskSource {
     fn clone(&self) -> DOMManipulationTaskSource {
-        DOMManipulationTaskSource(self.0.clone(), self.1)
+        DOMManipulationTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/file_reading.rs

@@ -18,7 +18,7 @@ pub struct FileReadingTaskSource(
 
 impl Clone for FileReadingTaskSource {
     fn clone(&self) -> FileReadingTaskSource {
-        FileReadingTaskSource(self.0.clone(), self.1)
+        FileReadingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/gamepad.rs

@@ -19,7 +19,7 @@ pub struct GamepadTaskSource(
 
 impl Clone for GamepadTaskSource {
     fn clone(&self) -> GamepadTaskSource {
-        GamepadTaskSource(self.0.clone(), self.1)
+        GamepadTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/history_traversal.rs

@@ -5,13 +5,13 @@
 use base::id::PipelineId;
 use crossbeam_channel::Sender;
 
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 
 #[derive(Clone, JSTraceable)]
-pub struct HistoryTraversalTaskSource(
+pub(crate) struct HistoryTraversalTaskSource(
     #[no_trace] pub Sender<MainThreadScriptMsg>,
     #[no_trace] pub PipelineId,
 );

components/script/task_source/media_element.rs

@@ -14,13 +14,13 @@ use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::event::SimpleEventTask;
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::window::Window;
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 
 #[derive(Clone, JSTraceable)]
-pub struct MediaElementTaskSource(
+pub(crate) struct MediaElementTaskSource(
     #[no_trace] pub Sender<MainThreadScriptMsg>,
     #[no_trace] pub PipelineId,
 );

components/script/task_source/networking.rs

@@ -16,7 +16,7 @@ pub struct NetworkingTaskSource(
 
 impl Clone for NetworkingTaskSource {
     fn clone(&self) -> NetworkingTaskSource {
-        NetworkingTaskSource(self.0.clone(), self.1)
+        NetworkingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/performance_timeline.rs

@@ -25,7 +25,7 @@ pub struct PerformanceTimelineTaskSource(
 
 impl Clone for PerformanceTimelineTaskSource {
     fn clone(&self) -> PerformanceTimelineTaskSource {
-        PerformanceTimelineTaskSource(self.0.clone(), self.1)
+        PerformanceTimelineTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/port_message.rs

@@ -18,7 +18,7 @@ pub struct PortMessageQueue(
 
 impl Clone for PortMessageQueue {
     fn clone(&self) -> PortMessageQueue {
-        PortMessageQueue(self.0.clone(), self.1)
+        PortMessageQueue(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/remote_event.rs

@@ -16,7 +16,7 @@ pub struct RemoteEventTaskSource(
 
 impl Clone for RemoteEventTaskSource {
     fn clone(&self) -> RemoteEventTaskSource {
-        RemoteEventTaskSource(self.0.clone(), self.1)
+        RemoteEventTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/rendering.rs

@@ -16,7 +16,7 @@ pub struct RenderingTaskSource(pub Box<dyn ScriptChan + Send>, #[no_trace] pub P
 
 impl Clone for RenderingTaskSource {
     fn clone(&self) -> RenderingTaskSource {
-        RenderingTaskSource(self.0.clone(), self.1)
+        RenderingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/timer.rs

@@ -19,7 +19,7 @@ pub struct TimerTaskSource(
 
 impl Clone for TimerTaskSource {
     fn clone(&self) -> TimerTaskSource {
-        TimerTaskSource(self.0.clone(), self.1)
+        TimerTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/user_interaction.rs

@@ -14,8 +14,8 @@ use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::event::{EventBubbles, EventCancelable, EventTask};
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::window::Window;
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 

components/script/task_source/websocket.rs

@@ -16,7 +16,7 @@ pub struct WebsocketTaskSource(
 
 impl Clone for WebsocketTaskSource {
     fn clone(&self) -> WebsocketTaskSource {
-        WebsocketTaskSource(self.0.clone(), self.1)
+        WebsocketTaskSource(self.0.as_boxed(), self.1)
     }
 }