[Chromoting] DirectX based capturer should always return a temporary error

webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 601 matching lines @@
   RTC_DCHECK(result);
   *result->mutable_updated_region() =
       surfaces_.current_frame()->get()->updated_region();
   return result;
 }
 
 void ScreenCapturerWinDirectx::Capture(const DesktopRegion& region) {
   RTC_DCHECK(callback_);
 
   if (!g_container->duplication && !DuplicateOutput()) {
-    // Failed to initialize desktop duplication.
-    callback_->OnCaptureResult(Result::ERROR_PERMANENT, nullptr);
+    // Failed to initialize desktop duplication. This usually happens when
+    // Windows is switching display mode. Retrying later usually resolve the

[Jamie, 2016/06/23 17:16:32]

s/resolve/resolves/

[Hzj_jie, 2016/06/23 18:42:07]

Done.

+    // issue.
+    callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
     return;
   }
 
   RTC_DCHECK(g_container->duplication);
   int64_t capture_start_time_nanos = rtc::TimeNanos();
 
   if (!SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)) {
     if (!set_thread_execution_state_failed_) {
       set_thread_execution_state_failed_ = true;
       LOG(LS_WARNING) << "Failed to make system & display power assertion: "
@@ skipping 83 matching lines @@
   }
 
   // If there is no shared_memory_factory_, last frame is stored in surfaces_
   // queue.
   std::unique_ptr<DesktopFrame> frame(
       new DxgiDesktopFrame(*surfaces_.current_frame()));
   callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
 }
 
 }  // namespace webrtc