cros: Replace BrowserThread::FILE in InputServiceProxy

chrome/browser/chromeos/device/input_service_proxy.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_DEVICE_INPUT_SERVICE_PROXY_H_
 #define CHROME_BROWSER_CHROMEOS_DEVICE_INPUT_SERVICE_PROXY_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/task_runner.h"
 #include "base/threading/thread_checker.h"
-#include "content/public/browser/browser_thread.h"
 #include "device/hid/input_service_linux.h"
 
 namespace chromeos {
 
 // Proxy to device::InputServiceLinux. Should be created and used on the UI
 // thread.
 class InputServiceProxy {
  public:
   typedef device::InputServiceLinux::InputDeviceInfo InputDeviceInfo;
 
@@ skipping 12 matching lines @@
   InputServiceProxy();
   ~InputServiceProxy();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   void GetDevices(const GetDevicesCallback& callback);
   void GetDeviceInfo(const std::string& id,
                      const GetDeviceInfoCallback& callback);
 
+  // Returns the TaskRunner for device::InputServiceLinux. Make it static so
+  // that all InputServiceProxy instances and code that needs access to
+  // device::InputServiceLinux uses the same TaskRunner.
+  static scoped_refptr<base::TaskRunner> GetInputServiceTaskRunner();

[fdoray, 2017/06/20 12:42:39]

Since it's important for callers that tasks posted to the returned TaskRunner
run in sequence, use SequencedTaskRunner as the return type.

[xiyuan, 2017/06/20 15:26:55]

Done.

+
   // Should be called once before any InputServiceProxy instance is created.
-  static void SetThreadIdForTesting(content::BrowserThread::ID thread_id);
+  static void SetUseUIThreadForTesting(bool use_ui_thread);
 
  private:
-  static content::BrowserThread::ID thread_identifier_;
-
   class ServiceObserver;
 
   void OnDeviceAdded(const device::InputServiceLinux::InputDeviceInfo& info);
   void OnDeviceRemoved(const std::string& id);
 
   base::ObserverList<Observer> observers_;
   std::unique_ptr<ServiceObserver> service_observer_;
 
-  base::ThreadChecker thread_checker_;
-
-  scoped_refptr<base::TaskRunner> task_runner_;
+  THREAD_CHECKER(thread_checker_);
 
   base::WeakPtrFactory<InputServiceProxy> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InputServiceProxy);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_DEVICE_INPUT_SERVICE_PROXY_H_