Let IndexedDBContextImpl create its own task runner

content/public/browser/indexed_db_context.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 28 matching lines @@
   // indexed db directory in the destination context needs to be empty.
   virtual void CopyOriginData(const GURL& origin_url,
                               IndexedDBContext* dest_context) = 0;
 
   // Get the file name of the local storage file for the given origin.
   virtual base::FilePath GetFilePathForTesting(
       const GURL& origin_url) const = 0;
 
   // 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>;
   virtual ~IndexedDBContext() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_