chore(sdk): Remove PinnedEventsCache entirely from RoomEventCache.

This patch removes deadcode about `PinnedEventsCache` in `RoomEventCache`.

Author: Hywan

crates/matrix-sdk/src/event_cache/caches/room/state.rs

@@ -36,7 +36,6 @@ use matrix_sdk_base::{
     sync::Timeline,
 };
 use matrix_sdk_common::executor::spawn;
-use once_cell::sync::OnceCell;
 use ruma::{
     EventId, OwnedEventId, OwnedRoomId, OwnedUserId,
     events::{
@@ -67,7 +66,6 @@ use super::{
         event_linked_chunk::EventLinkedChunk,
         lock,
         pagination::SharedPaginationStatus,
-        pinned_events::PinnedEventsCache,
         read_receipts::compute_unread_counts,
     },
     EventsOrigin, RoomEventCacheGenericUpdate, RoomEventCacheLinkedChunkUpdate,
@@ -111,9 +109,6 @@ pub struct RoomEventCacheState {
     /// permalink).
     event_focused_caches: HashMap<EventFocusedCacheKey, EventFocusedCache>,
 
-    /// Cache for pinned events in this room, initialized on-demand.
-    pinned_events_cache: OnceCell<PinnedEventsCache>,
-
     pagination_status: SharedObservable<SharedPaginationStatus>,
 
     /// A clone of [`super::RoomEventCacheInner::update_sender`].
@@ -261,7 +256,6 @@ impl LockedRoomEventCacheState {
             room_version_rules,
             waited_for_initial_prev_token: false,
             subscriber_count: Default::default(),
-            pinned_events_cache: OnceCell::new(),
             automatic_pagination,
         }))
     }
@@ -282,11 +276,6 @@ impl<'a> lock::Reload for RoomEventCacheStateLockWriteGuard<'a> {
     async fn reload(&mut self) -> Result<(), EventCacheError> {
         self.shrink_to_last_chunk().await?;
 
-        // Reload the pinned-events.
-        if let Some(pinned_events_cache) = self.pinned_events_cache.get_mut() {
-            pinned_events_cache.reload().await?;
-        }
-
         let diffs = self.state.room_linked_chunk.updates_as_vector_diffs();
 
         // Notify observers about the update.
@@ -380,13 +369,6 @@ impl<'a> RoomEventCacheStateLockWriteGuard<'a> {
         &mut self.state.room_linked_chunk
     }
 
-    /// Get a reference to the [`pinned_events_cache`] if it has been
-    /// initialized.
-    #[cfg(any(feature = "e2e-encryption", test))]
-    pub fn pinned_events_cache(&self) -> Option<&PinnedEventsCache> {
-        self.state.pinned_events_cache.get()
-    }
-
     /// Get a reference to all the live [`event_focused_caches`].
     #[cfg(feature = "e2e-encryption")]
     pub fn event_focused_caches(&self) -> impl Iterator<Item = &EventFocusedCache> {