Move non-gfx things out of gfx_traits and create a base crate (#32296)

For a long time, `gfx_traits` has held a lot of things unrelated to graphics
and also unrelated to the `gfx` crate (which is mostly about fonts).
This is a cleanup which does a few things:

1. Move non `gfx` crate things out of `gfx_traits`. This is important in
   order to prevent dependency cycles with a different integration between
   layout, script, and fonts.
2. Rename the `msg` crate to `base`. It didn't really contain anything
   to do with messages and instead mostly holds ids, which are used
   across many different crates in Servo. This new crate will hold the
   *rare* data types that are widely used.

Details:

 - All BackgroundHangMonitor-related things from base to a new
   `background_hang_monitor_api` crate.
 - Moved `TraversalDirection` to `script_traits`
 - Moved `Epoch`-related things from `gfx_traits` to `base`.
 - Moved `PrintTree` to base. This should be widely useful in Servo.
 - Moved `WebrenderApi` from `base` to `webrender_traits` and renamed it
   to `WebRenderFontApi`.

components/shared/script/Cargo.toml

@@ -11,6 +11,8 @@ name = "script_traits"
 path = "lib.rs"
 
 [dependencies]
+background_hang_monitor_api = { workspace = true }
+base = { workspace = true }
 bitflags = { workspace = true }
 bluetooth_traits = { workspace = true }
 canvas_traits = { workspace = true }
@@ -29,7 +31,6 @@ log = { workspace = true }
 malloc_size_of = { workspace = true }
 malloc_size_of_derive = { workspace = true }
 media = { path = "../../media" }
-msg = { workspace = true }
 net_traits = { workspace = true }
 pixels = { path = "../../pixels" }
 profile_traits = { workspace = true }

components/shared/script/lib.rs

@@ -20,6 +20,12 @@ use std::collections::{HashMap, VecDeque};
 use std::fmt;
 use std::sync::Arc;
 
+use background_hang_monitor_api::BackgroundHangMonitorRegister;
+use base::id::{
+    BlobId, BrowsingContextId, HistoryStateId, MessagePortId, PipelineId, PipelineNamespaceId,
+    TopLevelBrowsingContextId,
+};
+use base::Epoch;
 use bitflags::bitflags;
 use bluetooth_traits::BluetoothRequest;
 use canvas_traits::webgl::WebGLPipeline;
@@ -29,7 +35,6 @@ use devtools_traits::{DevtoolScriptControlMsg, ScriptToDevtoolsControlMsg, Worke
 use embedder_traits::{CompositorEventVariant, Cursor};
 use euclid::default::Point2D;
 use euclid::{Length, Rect, Scale, Size2D, UnknownUnit, Vector2D};
-use gfx_traits::Epoch;
 use http::{HeaderMap, Method};
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::Error as IpcError;
@@ -40,10 +45,6 @@ use log::warn;
 use malloc_size_of::malloc_size_of_is_0;
 use malloc_size_of_derive::MallocSizeOf;
 use media::WindowGLContext;
-use msg::constellation_msg::{
-    BackgroundHangMonitorRegister, BlobId, BrowsingContextId, HistoryStateId, MessagePortId,
-    PipelineId, PipelineNamespaceId, TopLevelBrowsingContextId,
-};
 use net_traits::image::base::Image;
 use net_traits::image_cache::ImageCache;
 use net_traits::request::{Referrer, RequestBody};
@@ -66,7 +67,7 @@ use crate::compositor::CompositorDisplayListInfo;
 pub use crate::script_msg::{
     DOMMessage, EventResult, HistoryEntryReplacement, IFrameSizeMsg, Job, JobError, JobResult,
     JobResultValue, JobType, LayoutMsg, LogEntry, SWManagerMsg, SWManagerSenders, ScopeThings,
-    ScriptMsg, ServiceWorkerMsg,
+    ScriptMsg, ServiceWorkerMsg, TraversalDirection,
 };
 use crate::serializable::{BlobData, BlobImpl};
 use crate::transferable::MessagePortImpl;

components/shared/script/script_msg.rs

@@ -5,18 +5,18 @@
 use std::collections::{HashMap, VecDeque};
 use std::fmt;
 
+use base::id::{
+    BroadcastChannelRouterId, BrowsingContextId, HistoryStateId, MessagePortId,
+    MessagePortRouterId, PipelineId, ServiceWorkerId, ServiceWorkerRegistrationId,
+    TopLevelBrowsingContextId,
+};
+use base::Epoch;
 use canvas_traits::canvas::{CanvasId, CanvasMsg};
 use devtools_traits::{ScriptToDevtoolsControlMsg, WorkerId};
 use embedder_traits::{EmbedderMsg, MediaSessionEvent};
 use euclid::default::Size2D as UntypedSize2D;
 use euclid::Size2D;
-use gfx_traits::Epoch;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use msg::constellation_msg::{
-    BroadcastChannelRouterId, BrowsingContextId, HistoryStateId, MessagePortId,
-    MessagePortRouterId, PipelineId, ServiceWorkerId, ServiceWorkerRegistrationId,
-    TopLevelBrowsingContextId, TraversalDirection,
-};
 use net_traits::request::RequestBuilder;
 use net_traits::storage_thread::StorageType;
 use net_traits::CoreResourceMsg;
@@ -492,3 +492,12 @@ pub enum SWManagerMsg {
     /// <https://github.com/servo/servo/issues/24660>
     PostMessageToClient,
 }
+
+/// The direction of a history traversal
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
+pub enum TraversalDirection {
+    /// Travel forward the given number of documents.
+    Forward(usize),
+    /// Travel backward the given number of documents.
+    Back(usize),
+}

components/shared/script/serializable.rs

@@ -11,8 +11,8 @@
 use std::cell::RefCell;
 use std::path::PathBuf;
 
+use base::id::BlobId;
 use malloc_size_of_derive::MallocSizeOf;
-use msg::constellation_msg::BlobId;
 use net_traits::filemanager_thread::RelativePos;
 use serde::{Deserialize, Serialize};
 use uuid::Uuid;

components/shared/script/transferable.rs

@@ -9,8 +9,8 @@
 
 use std::collections::VecDeque;
 
+use base::id::MessagePortId;
 use malloc_size_of_derive::MallocSizeOf;
-use msg::constellation_msg::MessagePortId;
 use serde::{Deserialize, Serialize};
 
 use crate::PortMessageTask;

components/shared/script/webdriver_msg.rs

@@ -6,11 +6,11 @@
 
 use std::collections::HashMap;
 
+use base::id::BrowsingContextId;
 use cookie::Cookie;
 use euclid::default::Rect;
 use hyper_serde::Serde;
 use ipc_channel::ipc::IpcSender;
-use msg::constellation_msg::BrowsingContextId;
 use serde::{Deserialize, Serialize};
 use servo_url::ServoUrl;
 use webdriver::common::{WebElement, WebFrame, WebWindow};