Reduce/remove usage of BrowserThread in content/browser/loader.

content/browser/loader/loader_globals.h

+// Copyright (c) 2017 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_BROWSER_LOADER_LOADER_GLOBALS_H_
+#define CONTENT_BROWSER_LOADER_LOADER_GLOBALS_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Contains global state for the network loader sources. Only one instance of
+// this class is active at any given point.
+class CONTENT_EXPORT LoaderGlobals {
+ public:
+  // Returns a pointer to the global instance.
+  static LoaderGlobals* Get();
+
+  LoaderGlobals(
+      const scoped_refptr<base::SingleThreadTaskRunner>& main_thread_runner,
+      const scoped_refptr<base::SingleThreadTaskRunner>& io_thread_runner);
+
+  ~LoaderGlobals();
+
+  scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner() const {
+    return io_thread_task_runner_;
+  }
+
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner() const {
+    return main_thread_task_runner_;
+  }
+
+ private:
+  // Task runner to be used for posting tasks to the main thread.
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
+
+  // Task runner to be used for posting tasks to the IO thread.
+  scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_LOADER_GLOBALS_H_