Removed FnvHash and transformed the rest to FxHashmap (#39233)

This should be the final PR for the Hash Function series that is
trivial.

Of note: I decided to transform `HashMapTracedValues<Atom,..>` to use
FxBuildHasher. This is likely not going to improve performance as Atom's
already have a unique u32 that is used as the Hash but it safes a few
bytes for the RandomState that is normally in the HashMap.

Signed-off-by: Narfinger <Narfinger@users.noreply.github.com>

Testing: Hash function changes should not change functionality, we
slightly decrease the size and unit tests still work.

Signed-off-by: Narfinger <Narfinger@users.noreply.github.com>

components/devtools/Cargo.toml

@@ -15,6 +15,7 @@ path = "lib.rs"
 base = { workspace = true }
 base64 = { workspace = true }
 chrono = { workspace = true }
+rustc-hash = { workspace = true }
 crossbeam-channel = { workspace = true }
 devtools_traits = { workspace = true }
 embedder_traits = { workspace = true }

components/devtools/id.rs

@@ -2,15 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-use std::collections::HashMap;
-
 use base::id::{BrowsingContextId, PipelineId, WebViewId};
+use rustc_hash::FxHashMap;
 
 #[derive(Debug, Default)]
 pub(crate) struct IdMap {
-    pub(crate) browser_ids: HashMap<WebViewId, u32>,
-    pub(crate) browsing_context_ids: HashMap<BrowsingContextId, u32>,
-    pub(crate) outer_window_ids: HashMap<PipelineId, u32>,
+    pub(crate) browser_ids: FxHashMap<WebViewId, u32>,
+    pub(crate) browsing_context_ids: FxHashMap<BrowsingContextId, u32>,
+    pub(crate) outer_window_ids: FxHashMap<PipelineId, u32>,
 }
 
 impl IdMap {

components/devtools/lib.rs

@@ -30,6 +30,7 @@ use embedder_traits::{AllowOrDeny, EmbedderMsg, EmbedderProxy};
 use ipc_channel::ipc::IpcSender;
 use log::{trace, warn};
 use resource::{ResourceArrayType, ResourceAvailable};
+use rustc_hash::FxHashMap;
 use serde::Serialize;
 use servo_rand::RngCore;
 
@@ -116,12 +117,12 @@ pub(crate) struct StreamId(u32);
 struct DevtoolsInstance {
     actors: Arc<Mutex<ActorRegistry>>,
     id_map: Arc<Mutex<IdMap>>,
-    browsing_contexts: HashMap<BrowsingContextId, String>,
+    browsing_contexts: FxHashMap<BrowsingContextId, String>,
     receiver: Receiver<DevtoolsControlMsg>,
-    pipelines: HashMap<PipelineId, BrowsingContextId>,
-    actor_workers: HashMap<WorkerId, String>,
+    pipelines: FxHashMap<PipelineId, BrowsingContextId>,
+    actor_workers: FxHashMap<WorkerId, String>,
     actor_requests: HashMap<String, String>,
-    connections: HashMap<StreamId, TcpStream>,
+    connections: FxHashMap<StreamId, TcpStream>,
     next_resource_id: u64,
 }
 
@@ -179,12 +180,12 @@ impl DevtoolsInstance {
         let instance = Self {
             actors,
             id_map: Arc::new(Mutex::new(IdMap::default())),
-            browsing_contexts: HashMap::new(),
-            pipelines: HashMap::new(),
+            browsing_contexts: FxHashMap::default(),
+            pipelines: FxHashMap::default(),
             receiver,
             actor_requests: HashMap::new(),
-            actor_workers: HashMap::new(),
-            connections: HashMap::new(),
+            actor_workers: FxHashMap::default(),
+            connections: FxHashMap::default(),
             next_resource_id: 1,
         };