chore(base): Remove LatestEvent::cached_event_origin_ts.

This patch removes the `LatestEvent::cached_event_origin_ts`.
It's no longer necessary to cache this value as the
`matrix_sdk_ui::room_list_service::sorter::recency` sorter no longer
uses it.

crates/matrix-sdk-base/src/latest_event.rs

@@ -14,7 +14,7 @@ use ruma::{
         call::{invite::SyncCallInviteEvent, notify::SyncCallNotifyEvent},
         relation::RelationType,
     },
-    MilliSecondsSinceUnixEpoch, MxcUri, OwnedEventId,
+    MxcUri, OwnedEventId,
 };
 use serde::{Deserialize, Serialize};
 
@@ -129,16 +129,6 @@ pub struct LatestEvent {
     /// The actual event.
     event: SyncTimelineEvent,
 
-    /// A copy of `Self::event::event::origin_server_ts`.
-    ///
-    /// This information can potentially be requested multiple times. Keeping a
-    /// copy here avoid to parse `Self::event::event` which is a `Raw<_>`.
-    ///
-    /// We `skip_serializing` instead of `skip` because deserializing is handled
-    /// by the custom `Deserialize` for `LatestEvent`.
-    #[serde(skip_serializing)]
-    cached_event_origin_server_ts: MilliSecondsSinceUnixEpoch,
-
     /// The member profile of the event' sender.
     #[serde(skip_serializing_if = "Option::is_none")]
     sender_profile: Option<MinimalRoomMemberEvent>,
@@ -175,11 +165,8 @@ impl<'de> Deserialize<'de> for LatestEvent {
 
         match serde_json::from_str::<SerializedLatestEvent>(raw.get()) {
             Ok(value) => {
-                let cached_event_origin_server_ts = extract_origin_server_ts(&value.event);
-
                 return Ok(LatestEvent {
                     event: value.event,
-                    cached_event_origin_server_ts,
                     sender_profile: value.sender_profile,
                     sender_name_is_ambiguous: value.sender_name_is_ambiguous,
                 });
@@ -189,11 +176,8 @@ impl<'de> Deserialize<'de> for LatestEvent {
 
         match serde_json::from_str::<SyncTimelineEvent>(raw.get()) {
             Ok(value) => {
-                let cached_event_origin_server_ts = extract_origin_server_ts(&value);
-
                 return Ok(LatestEvent {
                     event: value,
-                    cached_event_origin_server_ts,
                     sender_profile: None,
                     sender_name_is_ambiguous: None,
                 });
@@ -210,14 +194,7 @@ impl<'de> Deserialize<'de> for LatestEvent {
 impl LatestEvent {
     /// Create a new [`LatestEvent`] without the sender's profile.
     pub fn new(event: SyncTimelineEvent) -> Self {
-        let cached_event_origin_server_ts = extract_origin_server_ts(&event);
-
-        Self {
-            event,
-            cached_event_origin_server_ts,
-            sender_profile: None,
-            sender_name_is_ambiguous: None,
-        }
+        Self { event, sender_profile: None, sender_name_is_ambiguous: None }
     }
 
     /// Create a new [`LatestEvent`] with maybe the sender's profile.
@@ -226,9 +203,7 @@ impl LatestEvent {
         sender_profile: Option<MinimalRoomMemberEvent>,
         sender_name_is_ambiguous: Option<bool>,
     ) -> Self {
-        let cached_event_origin_server_ts = extract_origin_server_ts(&event);
-
-        Self { event, cached_event_origin_server_ts, sender_profile, sender_name_is_ambiguous }
+        Self { event, sender_profile, sender_name_is_ambiguous }
     }
 
     /// Transform [`Self`] into an event.
@@ -251,11 +226,6 @@ impl LatestEvent {
         self.event.event_id()
     }
 
-    /// Get the `origin_server_ts` of this latest event.
-    pub fn event_origin_server_ts(&self) -> MilliSecondsSinceUnixEpoch {
-        self.cached_event_origin_server_ts
-    }
-
     /// Check whether [`Self`] has a sender profile.
     pub fn has_sender_profile(&self) -> bool {
         self.sender_profile.is_some()
@@ -285,15 +255,6 @@ impl LatestEvent {
     }
 }
 
-fn extract_origin_server_ts(event: &SyncTimelineEvent) -> MilliSecondsSinceUnixEpoch {
-    event
-        .event
-        .get_field::<MilliSecondsSinceUnixEpoch>("origin_server_ts")
-        .ok()
-        .flatten()
-        .unwrap_or_else(|| MilliSecondsSinceUnixEpoch(0u8.into()))
-}
-
 #[cfg(test)]
 mod tests {
     use std::collections::BTreeMap;
@@ -559,7 +520,6 @@ mod tests {
         let initial = TestStruct {
             latest_event: LatestEvent {
                 event: event.clone(),
-                cached_event_origin_server_ts: MilliSecondsSinceUnixEpoch(0u8.into()),
                 sender_profile: None,
                 sender_name_is_ambiguous: None,
             },