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

remoting/host/desktop_capturer_proxy.cc

 // Copyright 2015 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/desktop_capturer_proxy.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 92 matching lines @@
     std::unique_ptr<webrtc::DesktopFrame> frame) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   caller_task_runner_->PostTask(
       FROM_HERE, base::Bind(&DesktopCapturerProxy::OnFrameCaptured, proxy_,
                             result, base::Passed(&frame)));
 }
 
 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,
                             base::Unretained(core_.get()), options));
 }
 
 DesktopCapturerProxy::~DesktopCapturerProxy() {
   capture_task_runner_->DeleteSoon(FROM_HERE, core_.release());
 }
 
@@ skipping 30 matching lines @@
 
 void DesktopCapturerProxy::OnFrameCaptured(
     webrtc::DesktopCapturer::Result result,
     std::unique_ptr<webrtc::DesktopFrame> frame) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   callback_->OnCaptureResult(result, std::move(frame));
 }
 
 }  // namespace remoting