Assert both display and system keep-alive on each capture.

media/video/capture/screen/screen_capturer_win.cc

 // Copyright (c) 2012 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 "media/video/capture/screen/screen_capturer.h"
 
 #include <windows.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 198 matching lines @@
 ScreenCapturerWin::~ScreenCapturerWin() {
 }
 
 void ScreenCapturerWin::InvalidateRegion(const SkRegion& invalid_region) {
   helper_.InvalidateRegion(invalid_region);
 }
 
 void ScreenCapturerWin::CaptureFrame() {
   base::Time capture_start_time = base::Time::Now();
 
-  // Force the system to power-up display hardware, if it has been suspended.
-  SetThreadExecutionState(ES_DISPLAY_REQUIRED);
+  // Request that the system not power-down the system, or the display hardware.
+  if (!SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)) {
+    LOG(WARNING) << "Failed to make system & display power assertion";

[alexeypa (please no reviews), 2013/02/11 17:02:28]

nit #1: LOG_GETLASTERROR(WARNING).

nit #2: this will flood the log if SetThreadExecutionState() fails all the time.
Add some rate limiting logic. For instance do not log the _same_ error unless X
seconds passed since the last one. 

[Wez, 2013/02/12 01:52:46]

I've settled on just logging the first failure per capturer, which should be
enough for the main debug value of determining why the user's machine fell
asleep. :)

+  }
 
   // Make sure the GDI capture resources are up-to-date.
   PrepareCaptureResources();
 
   // Copy screen bits to the current buffer.
   CaptureImage();
 
   const ScreenCaptureFrame* current_buffer = queue_.current_frame();
   const ScreenCaptureFrame* last_buffer = queue_.previous_frame();
   if (last_buffer) {
@@ skipping 346 matching lines @@
 void ScreenCapturer::Delegate::ReleaseSharedBuffer(
     scoped_refptr<SharedBuffer> buffer) {
 }
 
 // static
 scoped_ptr<ScreenCapturer> ScreenCapturer::Create() {
   return scoped_ptr<ScreenCapturer>(new ScreenCapturerWin());
 }
 
 }  // namespace media