[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/d3d_device.h

+/*
+ *  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.
+ */
+
+#ifndef MODULES_DESKTOP_CAPTURE_WIN_D3D_DEVICE_H_
+#define MODULES_DESKTOP_CAPTURE_WIN_D3D_DEVICE_H_
+
+#include <comdef.h>
+#include <wrl/client.h>
+#include <D3D11.h>
+#include <DXGI.h>
+
+#include <vector>
+
+namespace webrtc {
+
+// A wrapper of ID3D11Device and its corresponding context and IDXGIAdapter.
+// This class represents one video card in the system.
+class D3dDevice {

[Sergey Ulanov, 2016/07/08 22:36:53]

Do you really need this as a class and not a struct. If you think it should be a
class, then define constructor and destructor for this class.

[Hzj_jie, 2016/07/11 00:54:59]

I would still prefer to let this as a class. Moving Initialize logic into
constructor may eventually create a partial initialized instance. And we will
need to add a bool valid() const function to check its status, which should be
able to directly return from Initialize function. I will add a private
constructor to ensure the only way to create a D3dDevice instance is to use
EnumDevices function.

+ public:
+  // Initialize the D3dDevice from an IDXGIAdapter.
+  bool Initialize(const Microsoft::WRL::ComPtr<IDXGIAdapter>& adapter);

[Sergey Ulanov, 2016/07/08 22:36:53]

Do you need this as a separate method? Can initialization be done in
constructor? Or if you make this a struct then move initialization to
EnumDevices() and move EnumDevices to dxgi_duplicator_container.cc.

[Hzj_jie, 2016/07/11 00:54:59]

Same reason as above.

+
+  ID3D11Device* d3d_device() const {
+    return d3d_device_.Get();
+  }
+
+  ID3D11DeviceContext* context() const {
+    return context_.Get();
+  }
+
+  IDXGIDevice* dxgi_device() const {
+    return dxgi_device_.Get();
+  }
+
+  IDXGIAdapter* dxgi_adapter() const {
+    return dxgi_adapter_.Get();
+  }
+
+  // Returns all D3dDevices on the system. Returns an empty vector if anything
+  // wrong.
+  static std::vector<D3dDevice> EnumDevices();
+
+ private:
+  Microsoft::WRL::ComPtr<ID3D11Device> d3d_device_;
+  Microsoft::WRL::ComPtr<ID3D11DeviceContext> context_;
+  Microsoft::WRL::ComPtr<IDXGIDevice> dxgi_device_;
+  Microsoft::WRL::ComPtr<IDXGIAdapter> dxgi_adapter_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_DESKTOP_CAPTURE_WIN_D3D_DEVICE_H_