Add segmented GVL reference data maintenance

src/background/db/db-retention.js

@@ -89,6 +89,32 @@ async function purgeUnlockedEvidenceRecords(db) {
   });
 }
 
+function purgeGvlReferenceData(db) {
+  return new Promise((resolve, reject) => {
+    const clearedStores = {};
+    const tx = db.transaction(VENDORGET_GVL_REFERENCE_STORE_NAMES, "readwrite");
+
+    tx.onerror = () => reject(tx.error);
+    tx.onabort = () => reject(tx.error);
+    tx.oncomplete = () => {
+      resolve({
+        success: true,
+        clearedStores
+      });
+    };
+
+    for (const storeName of VENDORGET_GVL_REFERENCE_STORE_NAMES) {
+      const objectStore = tx.objectStore(storeName);
+      const countRequest = objectStore.count();
+
+      countRequest.onsuccess = () => {
+        clearedStores[storeName] = countRequest.result;
+        objectStore.clear();
+      };
+    }
+  });
+}
+
 function buildGvlWorkspaceProtectionIndex(db) {
   return new Promise((resolve, reject) => {
     const protectedSnapshotSha256 = new Set();