Several minor improvements of DirectX capturer

webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc

Index: webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
diff --git a/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc b/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
index 7478728143d0d8f93c274709e5d9207fc67073d4..6866d1e4c616a7c97c2581fc6f225380ed1bb8ba 100644
--- a/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
+++ b/webrtc/modules/desktop_capture/win/dxgi_texture_staging.cc
@@ -38,9 +38,13 @@ bool DxgiTextureStaging::InitializeStage(ID3D11Texture2D* texture) {
     return false;
   }
 
+  desc.ArraySize = 1;
   desc.BindFlags = 0;
   desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
+  desc.MipLevels = 1;
   desc.MiscFlags = 0;
+  desc.SampleDesc.Count = 1;
+  desc.SampleDesc.Quality = 0;
   desc.Usage = D3D11_USAGE_STAGING;
   if (stage_) {
     AssertStageAndSurfaceAreSameObject();
@@ -58,15 +62,15 @@ bool DxgiTextureStaging::InitializeStage(ID3D11Texture2D* texture) {
     RTC_DCHECK(!surface_);
   }
 
-  _com_error error = _com_error(device_.d3d_device()->CreateTexture2D(
-      &desc, nullptr, stage_.GetAddressOf()));
+  _com_error error = device_.d3d_device()->CreateTexture2D(
+      &desc, nullptr, stage_.GetAddressOf());
   if (error.Error() != S_OK || !stage_) {
     LOG(LS_ERROR) << "Failed to create a new ID3D11Texture2D as stage, error "
                   << error.ErrorMessage() << ", code " << error.Error();
     return false;
   }
 
-  error = _com_error(stage_.As(&surface_));
+  error = stage_.As(&surface_);
   if (error.Error() != S_OK || !surface_) {
     LOG(LS_ERROR) << "Failed to convert ID3D11Texture2D to IDXGISurface, error "
                   << error.ErrorMessage() << ", code " << error.Error();
@@ -123,7 +127,7 @@ bool DxgiTextureStaging::CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
   }
 
   rect_ = {0};
-  error = _com_error(surface_->Map(&rect_, DXGI_MAP_READ));
+  error = surface_->Map(&rect_, DXGI_MAP_READ);
   if (error.Error() != S_OK) {
     rect_ = {0};
     LOG(LS_ERROR) << "Failed to map the IDXGISurface to a bitmap, error "
@@ -135,7 +139,7 @@ bool DxgiTextureStaging::CopyFrom(const DXGI_OUTDUPL_FRAME_INFO& frame_info,
 }
 
 bool DxgiTextureStaging::DoRelease() {
-  _com_error error = _com_error(surface_->Unmap());
+  _com_error error = surface_->Unmap();
   if (error.Error() != S_OK) {
     stage_.Reset();
     surface_.Reset();