Let IndexedDBContextImpl create its own task runner

content/public/browser/indexed_db_context.h

Index: content/public/browser/indexed_db_context.h
diff --git a/content/public/browser/indexed_db_context.h b/content/public/browser/indexed_db_context.h
index ef9d61f441b0621320594688cbf3d133921bbb15..658fc6337d9d117cb73ddec2c1b69ae9d9e646e8 100644
--- a/content/public/browser/indexed_db_context.h
+++ b/content/public/browser/indexed_db_context.h
@@ -46,7 +46,7 @@ class IndexedDBContext : public base::RefCountedThreadSafe<IndexedDBContext> {
 
   // Set the task runner for tests if browser main loop is not initialized.
   virtual void SetTaskRunnerForTesting(
-      base::SequencedTaskRunner* task_runner) = 0;
+      const scoped_refptr<base::SequencedTaskRunner>& task_runner) = 0;

[gab, 2017/06/13 15:31:23]

Taking scoped_refptr by value and std::move() in impl is the prefered style
since C++11

 
  protected:
   friend class base::RefCountedThreadSafe<IndexedDBContext>;