Bug 1878841 - Add support for pausing IndexedDB connection thread during connection idle maintenance; r=dom-storage-reviewers,jari

Differential Revision: https://phabricator.services.mozilla.com/D200780

dom/indexedDB/ActorsParent.cpp

@@ -6933,6 +6933,12 @@ Result<bool, nsresult> DatabaseConnection::ReclaimFreePagesWhileIdle(
 
   AUTO_PROFILER_LABEL("DatabaseConnection::ReclaimFreePagesWhileIdle", DOM);
 
+  uint32_t pauseOnConnectionThreadMs = StaticPrefs::
+      dom_indexedDB_connectionIdleMaintenance_pauseOnConnectionThreadMs();
+  if (pauseOnConnectionThreadMs > 0) {
+    PR_Sleep(PR_MillisecondsToInterval(pauseOnConnectionThreadMs));
+  }
+
   // Make sure we don't keep working if anything else needs this thread.
   nsIThread* currentThread = NS_GetCurrentThread();
   MOZ_ASSERT(currentThread);

modules/libpref/init/StaticPrefList.yaml

@@ -2754,6 +2754,13 @@
   value: true
   mirror: always
 
+# A pref that is used to slow down connection idle maintenance for testing
+# purposes.
+- name: dom.indexedDB.connectionIdleMaintenance.pauseOnConnectionThreadMs
+  type: RelaxedAtomicUint32
+  value: 0
+  mirror: always
+
 # Whether or not indexedDB test mode is enabled.
 - name: dom.indexedDB.testing
   type: RelaxedAtomicBool