clippy: Fix warnings in components/constellation (#31610)

* clippy: fix warnings in components/constellation

* fix: review comments

components/constellation/session_history.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use std::cmp::PartialEq;
-use std::{fmt, mem};
+use std::fmt;
 
 use euclid::Size2D;
 use log::debug;
@@ -44,7 +44,7 @@ impl JointSessionHistory {
     pub fn push_diff(&mut self, diff: SessionHistoryDiff) -> Vec<SessionHistoryDiff> {
         debug!("pushing a past entry; removing future");
         self.past.push(diff);
-        mem::replace(&mut self.future, vec![])
+        std::mem::take(&mut self.future)
     }
 
     pub fn replace_reloader(&mut self, old_reloader: NeedsToReload, new_reloader: NeedsToReload) {
@@ -59,12 +59,12 @@ impl JointSessionHistory {
         history_state_id: HistoryStateId,
         url: ServoUrl,
     ) {
-        if let Some(SessionHistoryDiff::PipelineDiff {
+        if let Some(SessionHistoryDiff::Pipeline {
             ref mut new_history_state_id,
             ref mut new_url,
             ..
         }) = self.past.iter_mut().find(|diff| match diff {
-            SessionHistoryDiff::PipelineDiff {
+            SessionHistoryDiff::Pipeline {
                 pipeline_reloader: NeedsToReload::No(id),
                 ..
             } => pipeline_id == *id,
@@ -74,12 +74,12 @@ impl JointSessionHistory {
             *new_url = url.clone();
         }
 
-        if let Some(SessionHistoryDiff::PipelineDiff {
+        if let Some(SessionHistoryDiff::Pipeline {
             ref mut old_history_state_id,
             ref mut old_url,
             ..
         }) = self.future.iter_mut().find(|diff| match diff {
-            SessionHistoryDiff::PipelineDiff {
+            SessionHistoryDiff::Pipeline {
                 pipeline_reloader: NeedsToReload::No(id),
                 ..
             } => pipeline_id == *id,
@@ -93,14 +93,14 @@ impl JointSessionHistory {
     pub fn remove_entries_for_browsing_context(&mut self, context_id: BrowsingContextId) {
         debug!("{}: Removing entries for browsing context", context_id);
         self.past.retain(|diff| match diff {
-            SessionHistoryDiff::BrowsingContextDiff {
+            SessionHistoryDiff::BrowsingContext {
                 browsing_context_id,
                 ..
             } => *browsing_context_id != context_id,
             _ => true,
         });
         self.future.retain(|diff| match diff {
-            SessionHistoryDiff::BrowsingContextDiff {
+            SessionHistoryDiff::BrowsingContext {
                 browsing_context_id,
                 ..
             } => *browsing_context_id != context_id,
@@ -180,7 +180,7 @@ impl PartialEq for NeedsToReload {
 #[derive(Debug)]
 pub enum SessionHistoryDiff {
     /// Represents a diff where the active pipeline of an entry changed.
-    BrowsingContextDiff {
+    BrowsingContext {
         /// The browsing context whose pipeline changed
         browsing_context_id: BrowsingContextId,
         /// The previous pipeline (used when traversing into the past)
@@ -189,7 +189,7 @@ pub enum SessionHistoryDiff {
         new_reloader: NeedsToReload,
     },
     /// Represents a diff where the active state of a pipeline changed.
-    PipelineDiff {
+    Pipeline {
         /// The pipeline whose history state changed.
         pipeline_reloader: NeedsToReload,
         /// The old history state id.
@@ -201,7 +201,7 @@ pub enum SessionHistoryDiff {
         /// The new url
         new_url: ServoUrl,
     },
-    HashDiff {
+    Hash {
         pipeline_reloader: NeedsToReload,
         old_url: ServoUrl,
         new_url: ServoUrl,
@@ -212,7 +212,7 @@ impl SessionHistoryDiff {
     /// Returns the old pipeline id if that pipeline is still alive, otherwise returns `None`
     pub fn alive_old_pipeline(&self) -> Option<PipelineId> {
         match *self {
-            SessionHistoryDiff::BrowsingContextDiff {
+            SessionHistoryDiff::BrowsingContext {
                 ref old_reloader, ..
             } => match *old_reloader {
                 NeedsToReload::No(pipeline_id) => Some(pipeline_id),
@@ -225,7 +225,7 @@ impl SessionHistoryDiff {
     /// Returns the new pipeline id if that pipeline is still alive, otherwise returns `None`
     pub fn alive_new_pipeline(&self) -> Option<PipelineId> {
         match *self {
-            SessionHistoryDiff::BrowsingContextDiff {
+            SessionHistoryDiff::BrowsingContext {
                 ref new_reloader, ..
             } => match *new_reloader {
                 NeedsToReload::No(pipeline_id) => Some(pipeline_id),
@@ -242,7 +242,7 @@ impl SessionHistoryDiff {
         reloader: &NeedsToReload,
     ) {
         match *self {
-            SessionHistoryDiff::BrowsingContextDiff {
+            SessionHistoryDiff::BrowsingContext {
                 ref mut old_reloader,
                 ref mut new_reloader,
                 ..
@@ -254,7 +254,7 @@ impl SessionHistoryDiff {
                     *new_reloader = reloader.clone();
                 }
             },
-            SessionHistoryDiff::PipelineDiff {
+            SessionHistoryDiff::Pipeline {
                 ref mut pipeline_reloader,
                 ..
             } => {
@@ -262,7 +262,7 @@ impl SessionHistoryDiff {
                     *pipeline_reloader = reloader.clone();
                 }
             },
-            SessionHistoryDiff::HashDiff {
+            SessionHistoryDiff::Hash {
                 ref mut pipeline_reloader,
                 ..
             } => {