Log error messages in windows video capture

media/video/capture/win/video_capture_device_mf_win.cc

Index: media/video/capture/win/video_capture_device_mf_win.cc
diff --git a/media/video/capture/win/video_capture_device_mf_win.cc b/media/video/capture/win/video_capture_device_mf_win.cc
index de1f6eb2dfff6056305637b94937a86eedae0b95..5fea3b00a15cc9c7d0ce4d230cccad7a5a0deb19 100644
--- a/media/video/capture/win/video_capture_device_mf_win.cc
+++ b/media/video/capture/win/video_capture_device_mf_win.cc
@@ -332,10 +332,13 @@ void VideoCaptureDeviceMFWin::OnIncomingCapturedData(
 }
 
 void VideoCaptureDeviceMFWin::OnError(HRESULT hr) {
-  std::string log_msg = base::StringPrintf("VideoCaptureDeviceMFWin: %x", hr);
-  DLOG(ERROR) << log_msg;
+  const std::string log_msg =
+      base::StringPrintf("VideoCaptureDeviceMFWin: %x", hr);
+  const std::string last_error_message =
+      logging::SystemErrorCodeToString(logging::GetLastSystemErrorCode());
+  DPLOG(ERROR) << log_msg;

[mcasas, 2014/08/26 15:38:18]

l.338 will in all probability clear the last error id,
so perhaps here you should do:
DLOG(ERROR) << log_msg << ", OS message: " << last_error_message;

Note DLOG(ERROR) != DVLOG(1) 

[magjed_chromium, 2014/08/26 17:20:28]

Done. Btw, I don't think GetLastSystemErrorCode clears the last error (from
reading the documentation, not testing).

   if (client_.get())
-    client_->OnError(log_msg);
+    client_->OnError(log_msg + " : " + last_error_message);
 }
 
 }  // namespace media