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

remoting/host/screen_saver_blocker.cc

Index: remoting/host/screen_saver_blocker.cc
diff --git a/remoting/host/screen_saver_blocker.cc b/remoting/host/screen_saver_blocker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..692de054e498c24b4b6ccc6ad15d89d0f982de29
--- /dev/null
+++ b/remoting/host/screen_saver_blocker.cc
@@ -0,0 +1,43 @@
+// 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.
+
+#include "remoting/host/screen_saver_blocker.h"
+
+#include <utility>
+
+#include "base/logging.h"
+#include "remoting/base/auto_thread_task_runner.h"
+#include "remoting/host/host_status_monitor.h"
+
+namespace remoting {
+
+ScreenSaverBlocker::ScreenSaverBlocker(
+    base::WeakPtr<HostStatusMonitor> monitor,
+    std::unique_ptr<ChromotingHostContext>&& context)
+    : monitor_(monitor),
+      context_(std::move(context)) {
+  DCHECK(monitor_);
+  monitor_->AddStatusObserver(this);
+}
+
+ScreenSaverBlocker::~ScreenSaverBlocker() {
+  if (monitor_.get()) {
+    monitor_->RemoveStatusObserver(this);
+  }
+}
+
+void ScreenSaverBlocker::OnClientConnected(const std::string& jid) {
+  blocker_.reset(new device::PowerSaveBlocker(
+      device::PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep,
+      device::PowerSaveBlocker::kReasonVideoPlayback,

[Sergey Ulanov, 2016/07/08 21:31:47]

Why not kReasonOther? 

[Hzj_jie, 2016/07/10 22:04:57]

Done.

+      "Remoting session is active",
+      context_->ui_task_runner(),
+      context_->file_task_runner()));
+}
+
+void ScreenSaverBlocker::OnClientDisconnected(const std::string& jid) {
+  blocker_.reset();
+}
+
+}  // namespace remoting