Fix lack of error handling in parts of backing store.

Errors propagating here could cause the bot to have only partially
synced by propagating all the way up to the sync response handling in
the bot-sdk.

#691.

src/backingstore/better-sqlite3/SqliteRoomStateBackingStore.ts

@@ -67,7 +67,7 @@ export class SqliteRoomStateBackingStore
     this.ensureSchema();
   }
 
-  public handleRevision(
+  private updateBackingStore(
     revision: RoomStateRevision,
     changes: StateChange[]
   ): void {
@@ -102,9 +102,37 @@ export class SqliteRoomStateBackingStore
     });
     const roomInfo = this.getRoomMeta(revision.room.toRoomIDOrAlias());
     if (roomInfo === undefined) {
-      doCompleteWriteback();
+      try {
+        doCompleteWriteback();
+      } catch (e) {
+        log.error(
+          `Unable to create initial room state for ${revision.room.toPermalink()} into the room state backing store`,
+          e
+        );
+      }
     } else {
-      replace(changes.map((change) => change.state));
+      try {
+        replace(changes.map((change) => change.state));
+      } catch (e) {
+        log.error(
+          `Unable to update the room state for ${revision.room.toPermalink()} as a result of ${changes.length} changes`,
+          e
+        );
+      }
+    }
+  }
+
+  public handleRevision(
+    revision: RoomStateRevision,
+    changes: StateChange[]
+  ): void {
+    try {
+      this.updateBackingStore(revision, changes);
+    } catch (e) {
+      log.error(
+        `Unable to update the backing store for revision of the room ${revision.room.toPermalink()}`,
+        e
+      );
     }
   }