Add algorithm for processing constraints for video content capture.

content/renderer/media/media_stream_constraints_util_video_content.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_CONSTRAINTS_UTIL_VIDEO_CONTENT_H_
+#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_CONSTRAINTS_UTIL_VIDEO_CONTENT_H_
+
+#include <string>
+
+#include "content/common/content_export.h"
+#include "media/capture/video_capture_types.h"
+#include "third_party/webrtc/base/optional.h"
+
+namespace blink {
+class WebMediaConstraints;
+}
+
+namespace content {
+
+struct CONTENT_EXPORT VideoContentCaptureSourceSelectionResult {
+  // Creates a result without value and with an empty |failed_constraint_name|.
+  VideoContentCaptureSourceSelectionResult();
+
+  VideoContentCaptureSourceSelectionResult(
+      const VideoContentCaptureSourceSelectionResult& other);
+  VideoContentCaptureSourceSelectionResult& operator=(
+      const VideoContentCaptureSourceSelectionResult& other);
+  VideoContentCaptureSourceSelectionResult(
+      VideoContentCaptureSourceSelectionResult&& other);
+  VideoContentCaptureSourceSelectionResult& operator=(
+      VideoContentCaptureSourceSelectionResult&& other);
+  ~VideoContentCaptureSourceSelectionResult();
+
+  bool HasValue() const;
+
+  // Convenience accessors for fields embedded in the capture_params field.
+  int Height() const;
+  int Width() const;
+  float FrameRate() const;
+  media::ResolutionChangePolicy ResolutionChangePolicy() const;
+

[hta - Chromium, 2017/03/08 13:34:09]

Wonder if you could get away with a "private" here.

[Guido Urdaneta, 2017/03/09 14:38:38]

Done. Changed to a class.

+  std::string device_id;
+  rtc::Optional<bool> noise_reduction;
+  media::VideoCaptureParams capture_params;
+  const char* failed_constraint_name;
+};
+
+VideoContentCaptureSourceSelectionResult CONTENT_EXPORT
+SelectVideoContentCaptureSourceSettings(
+    const blink::WebMediaConstraints& constraints);
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_CONSTRAINTS_UTIL_VIDEO_CONTENT_H_