Remove explicit use of exclusive mode on database option

The database option `exclusive_locking` is enabled by default.

NOTE: This CL has no functional changes.

It was used to be recommended to explicitly specify it to avoid using
the default DatabaseOptions constructor which had `exclusive_locking`
to false (due historical reason related to unittests migration).

The following CL [landed] fixes the default constructor and by
default all database as using the `exclusive_locking` mode.
see: https://chromium-review.googlesource.com/c/chromium/src/+/5029223

The recommendation from now is to explicitly specify the non
exclusive case with an explanation of why the database can be
accessed in that mode.

Bug: 1120969
Change-Id: Ib278d967c76c1ea8494ebaa4bb1723f0fb74c30e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5251553
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Ayu Ishii <ayui@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1256381}

chrome/browser/extensions/activity_log/activity_database.cc

@@ -40,7 +40,6 @@ static const int kSizeThresholdForFlush = 200;
 ActivityDatabase::ActivityDatabase(ActivityDatabase::Delegate* delegate)
     : delegate_(delegate),
       db_({
-          .exclusive_locking = true,
           .page_size = 4096,
           .cache_size = 32,
           // TODO(pwnall): Add a meta table and remove this option.

chrome/browser/predictors/predictor_database.cc

@@ -100,8 +100,6 @@ PredictorDatabaseInternal::~PredictorDatabaseInternal() {
 
 void PredictorDatabaseInternal::Initialize() {
   DCHECK(db_task_runner_->RunsTasksInCurrentSequence());
-  // TODO(tburkard): figure out if we need this.
-  //  db_->set_exclusive_locking();
   if (autocomplete_table_->IsCancelled() ||
       resource_prefetch_tables_->IsCancelled()) {
     return;

components/blocklist/opt_out_blocklist/sql/opt_out_store_sql.cc

@@ -390,7 +390,6 @@ void OptOutStoreSQL::LoadBlockList(
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   if (!db_) {
     db_ = std::make_unique<sql::Database>(sql::DatabaseOptions{
-        .exclusive_locking = true,
         // The entry size should be between 11 and 10 + x bytes, where x is the
         // the length of the host name string in bytes.
         // The total number of entries per host is bounded at 32, and the total

components/offline_pages/core/background/request_queue_store.cc

@@ -587,8 +587,8 @@ RequestQueueStore::~RequestQueueStore() {
 
 void RequestQueueStore::Initialize(InitializeCallback callback) {
   DCHECK(!db_);
-  db_ = std::make_unique<sql::Database>(sql::DatabaseOptions{
-      .exclusive_locking = true, .page_size = 4096, .cache_size = 500});
+  db_ = std::make_unique<sql::Database>(
+      sql::DatabaseOptions{.page_size = 4096, .cache_size = 500});
 
   background_task_runner_->PostTaskAndReplyWithResult(
       FROM_HERE, base::BindOnce(&InitDatabaseSync, db_.get(), db_file_path_),

components/offline_pages/task/sql_store_base.cc

@@ -100,7 +100,6 @@ void SqlStoreBase::Initialize(base::OnceClosure pending_command) {
   // This is how we reset a pointer and provide deleter. This is necessary to
   // ensure that we can close the store more than once.
   db_ = DatabaseUniquePtr(new sql::Database({// These values are default.
-                                             .exclusive_locking = true,
                                              .page_size = 4096,
                                              .cache_size = 500}),
                           base::OnTaskRunnerDeleter(background_task_runner_));

content/browser/attribution_reporting/attribution_storage_sql.cc

@@ -467,9 +467,7 @@ AttributionStorageSql::AttributionStorageSql(
     : path_to_database_(user_data_directory.empty()
                             ? base::FilePath()
                             : DatabasePath(user_data_directory)),
-      db_(sql::DatabaseOptions{.exclusive_locking = true,
-                               .page_size = 4096,
-                               .cache_size = 32}),
+      db_(sql::DatabaseOptions{.page_size = 4096, .cache_size = 32}),
       delegate_(std::move(delegate)),
       rate_limit_table_(delegate_.get()) {
   DCHECK(delegate_);

content/browser/browsing_topics/browsing_topics_site_data_storage.cc

@@ -244,8 +244,8 @@ bool BrowsingTopicsSiteDataStorage::LazyInit() {
   if (db_init_status_ != InitStatus::kUnattempted)
     return db_init_status_ == InitStatus::kSuccess;
 
-  db_ = std::make_unique<sql::Database>(sql::DatabaseOptions{
-      .exclusive_locking = true, .page_size = 4096, .cache_size = 32});
+  db_ = std::make_unique<sql::Database>(
+      sql::DatabaseOptions{.page_size = 4096, .cache_size = 32});
   db_->set_histogram_tag("BrowsingTopics");
 
   // base::Unretained is safe here because this BrowsingTopicsSiteDataStorage

content/browser/tracing/trace_report/trace_report_database.cc

@@ -82,9 +82,7 @@ ClientTraceReport::ClientTraceReport() = default;
 ClientTraceReport::~ClientTraceReport() = default;
 
 TraceReportDatabase::TraceReportDatabase()
-    : database_(sql::DatabaseOptions{.exclusive_locking = true,
-                                     .page_size = 4096,
-                                     .cache_size = 128}) {
+    : database_(sql::DatabaseOptions{.page_size = 4096, .cache_size = 128}) {
   DETACH_FROM_SEQUENCE(sequence_checker_);
 }
 

services/network/trust_tokens/trust_token_database_owner.cc

@@ -90,10 +90,6 @@ NOINLINE TrustTokenDatabaseOwner::TrustTokenDatabaseOwner(
           db_task_runner)),
       db_task_runner_(db_task_runner),
       backing_database_(std::make_unique<sql::Database>(sql::DatabaseOptions{
-          // As they work on deleting the feature (crbug.com/1120969), sql/
-          // owners prefer to see which clients are explicitly okay with using
-          // exclusive locking (the default).
-          .exclusive_locking = true,
           .page_size = 4096,
           .cache_size = 500,
           // TODO(pwnall): Add a meta table and remove this option.

storage/browser/database/database_tracker.cc

@@ -112,7 +112,6 @@ DatabaseTracker::DatabaseTracker(
                   ? profile_path_.Append(kIncognitoDatabaseDirectoryName)
                   : profile_path_.Append(kDatabaseDirectoryName)),
       db_(std::make_unique<sql::Database>(sql::DatabaseOptions{
-          .exclusive_locking = true,
           .page_size = 4096,
           .cache_size = 500,
       })),