[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/dxgi_context.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_DXGI_CONTEXT_H_
+#define MODULES_DESKTOP_CAPTURE_WIN_DXGI_CONTEXT_H_
+
+#include <vector>
+
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+
+namespace webrtc {
+
+struct DxgiContext {

[Sergey Ulanov, 2016/07/26 00:48:51]

Add comment to explain how this class is used.

[Hzj_jie, 2016/07/26 02:13:01]

Done.

+ private:
+  friend class DxgiOutputDuplicator;
+  friend class DxgiAdapterDuplicator;
+  friend class DxgiDuplicatorContainer;

[Sergey Ulanov, 2016/07/26 00:48:51]

So here you have struct with all fields private and accessible only by these
classes. Do you really need it?
In either case I don't think style guide allows anything to be private in
structs, so this would have to be a class.

[Hzj_jie, 2016/07/26 02:13:01]

Done.

+
+  // The time this DxgiContext got initialized. DxgiDuplicationContainer uses
+  // this time to decide whether current DxgiContext needs to be updated.
+  int64_t initialize_time_nanos_ = 0;

[Sergey Ulanov, 2016/07/26 00:48:51]

remove _ suffix. It's used only for class fields, not in structs.

[Hzj_jie, 2016/07/26 02:13:01]

Changed into class.

+
+  // Child DxgiContext belongs to this DxgiContext.
+  std::vector<DxgiContext> contexts_;

[Sergey Ulanov, 2016/07/26 00:48:51]

Why do you need a tree of contexts?

[Hzj_jie, 2016/07/26 02:13:01]

One update_region_ is for one DxgiOutputDuplicator. So each
DxgiAdapterDuplicator will have a set of DxgiContexts for each of its
DxgiOutputDuplicator, and so does DxgiDuplicatorContainer.

+
+  DesktopRegion updated_region_;

[Sergey Ulanov, 2016/07/26 00:48:51]

Add comment to make it clear what's stored here.

[Hzj_jie, 2016/07/26 02:13:01]

Done.

+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_DESKTOP_CAPTURE_WIN_DXGI_CONTEXT_H_