[Chromoting] Use device::PowerSaveBlocker to block screen saver

remoting/host/host_power_save_blocker.h

Index: remoting/host/host_power_save_blocker.h
diff --git a/remoting/host/host_power_save_blocker.h b/remoting/host/host_power_save_blocker.h
new file mode 100644
index 0000000000000000000000000000000000000000..a704355c729ac7ff012b21547bb62b45f683f22d
--- /dev/null
+++ b/remoting/host/host_power_save_blocker.h
@@ -0,0 +1,53 @@
+// Copyright 2016 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 REMOTING_HOST_HOST_POWER_SAVER_BLOCKER_H_
+#define REMOTING_HOST_HOST_POWER_SAVER_BLOCKER_H_
+
+#include <memory>
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "device/power_save_blocker/power_save_blocker.h"
+#include "remoting/host/host_status_observer.h"
+
+namespace base {
+
+class SequencedTaskRunner;
+class SingleThreadTaskRunner;
+
+}  // namespace base
+
+namespace remoting {
+
+class AutoThreadTaskRunner;
+class HostStatusMonitor;
+
+// A HostStatusObserver to block screen saver from taking effect during the
+// lifetime of a remoting connection.
+class HostPowerSaveBlocker : public HostStatusObserver {
+ public:
+  HostPowerSaveBlocker(
+      base::WeakPtr<HostStatusMonitor> monitor,
+      const scoped_refptr<base::SequencedTaskRunner>& ui_task_runner,
+      const scoped_refptr<base::SingleThreadTaskRunner>& file_task_runner);

[Sergey Ulanov, 2016/07/14 19:52:48]

I think these both should be SingleThreadTaskRunner. Why do you need
SequencedTaskRunner for ui_task_runner?

[Hzj_jie, 2016/07/14 23:20:03]

Follow the definition of PowerSaveBlocker.

[Sergey Ulanov, 2016/07/14 23:30:56]

I'm not sure why they used SequencedTaskRunner there, but I don't see any reason
to copy it. Please use SingleThreadTaskRunner for both task runners.

[Hzj_jie, 2016/07/15 02:12:00]

Done.

+
+  ~HostPowerSaveBlocker() override;
+
+  void OnClientConnected(const std::string& jid) override;
+  void OnClientDisconnected(const std::string& jid) override;
+
+ private:
+  friend class HostPowerSaveBlockerTest;
+
+  base::WeakPtr<HostStatusMonitor> monitor_;
+  scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
+  std::unique_ptr<device::PowerSaveBlocker> blocker_;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_HOST_POWER_SAVER_BLOCKER_H_