Let IndexedDBContextImpl create its own task runner

content/browser/indexed_db/indexed_db_context_impl.cc

Index: content/browser/indexed_db/indexed_db_context_impl.cc
diff --git a/content/browser/indexed_db/indexed_db_context_impl.cc b/content/browser/indexed_db/indexed_db_context_impl.cc
index 5357e60c6842a6815987eb9e0dcb30dff1aca9b0..b2d7323cc7e765a4e1114a5d7a76081bf8b1d93c 100644
--- a/content/browser/indexed_db/indexed_db_context_impl.cc
+++ b/content/browser/indexed_db/indexed_db_context_impl.cc
@@ -17,6 +17,7 @@
 #include "base/sequenced_task_runner.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
@@ -109,12 +110,14 @@ void ClearSessionOnlyOrigins(
 IndexedDBContextImpl::IndexedDBContextImpl(
     const base::FilePath& data_path,
     storage::SpecialStoragePolicy* special_storage_policy,
-    storage::QuotaManagerProxy* quota_manager_proxy,
-    scoped_refptr<base::SequencedTaskRunner> task_runner)
+    storage::QuotaManagerProxy* quota_manager_proxy)
     : force_keep_session_state_(false),
       special_storage_policy_(special_storage_policy),
       quota_manager_proxy_(quota_manager_proxy),
-      task_runner_(std::move(task_runner)) {
+      task_runner_(base::CreateSequencedTaskRunnerWithTraits(
+          {base::MayBlock(), base::WithBaseSyncPrimitives(),
+           base::TaskPriority::USER_VISIBLE,
+           base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN})) {
   IDB_TRACE("init");
   if (!data_path.empty())
     data_path_ = data_path.Append(kIndexedDBDirectory);
@@ -426,8 +429,7 @@ base::FilePath IndexedDBContextImpl::GetFilePathForTesting(
 }
 
 void IndexedDBContextImpl::SetTaskRunnerForTesting(
-    base::SequencedTaskRunner* task_runner) {
-  DCHECK(!task_runner_.get());
+    const scoped_refptr<base::SequencedTaskRunner>& task_runner) {
   task_runner_ = task_runner;
 }