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

remoting/host/desktop_capturer_proxy.cc

Index: remoting/host/desktop_capturer_proxy.cc
diff --git a/remoting/host/desktop_capturer_proxy.cc b/remoting/host/desktop_capturer_proxy.cc
index af9f1629402968ca0a4a4030adefa807128ea379..9dca84c3a0104e313ccfb66808c521c6bcd572ef 100644
--- a/remoting/host/desktop_capturer_proxy.cc
+++ b/remoting/host/desktop_capturer_proxy.cc
@@ -110,8 +110,17 @@ void DesktopCapturerProxy::Core::OnCaptureResult(
 
 DesktopCapturerProxy::DesktopCapturerProxy(
     scoped_refptr<base::SingleThreadTaskRunner> capture_task_runner,
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner,
     const webrtc::DesktopCaptureOptions& options)
-    : capture_task_runner_(capture_task_runner), weak_factory_(this) {
+    : capture_task_runner_(capture_task_runner),
+      power_save_blocker_(
+          device::PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep,
+          device::PowerSaveBlocker::kReasonVideoPlayback,
+          "Capturing screens",
+          ui_task_runner,
+          blocking_task_runner),
+      weak_factory_(this) {
   core_.reset(new Core(weak_factory_.GetWeakPtr()));
   capture_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Core::CreateCapturer,