[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/win/dxgi_texture.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.
+ */
+
+#include "webrtc/modules/desktop_capture/win/dxgi_texture.h"
+
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+
+namespace webrtc {
+
+namespace {
+
+class DxgiDesktopFrame : public DesktopFrame {
+ public:
+  explicit DxgiDesktopFrame(const DxgiTexture& texture)
+      : DesktopFrame(texture.desktop_rect().size(),
+                     texture.pitch(),
+                     texture.bits(),
+                     nullptr) {}
+
+  virtual ~DxgiDesktopFrame() = default;
+};
+
+}  // namespace
+
+DxgiTexture::DxgiTexture(const DesktopRect& desktop_rect)
+    : desktop_rect_(desktop_rect) {}
+
+const DesktopFrame& DxgiTexture::AsDesktopFrame() {
+  if (!frame_) {
+    frame_.reset(new DxgiDesktopFrame(*this));
+  }
+  return *frame_;
+}
+
+bool DxgiTexture::Release() {
+  frame_.reset();
+  return DoRelease();
+}
+
+}  // namespace webrtc