Use spec-compliant algorithm for video content-capture deviceId selection in getUserMedia.

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 "base/logging.h"
 #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 {
 
 class CONTENT_EXPORT VideoContentCaptureSourceSelectionResult {
  public:
+  // Creates a result without value and with an empty failed constraint name.
+  VideoContentCaptureSourceSelectionResult();
+
   // Creates a result without value and with the given |failed_constraint_name|.
   // Does not take ownership of |failed_constraint_name|, so it must be null or
   // point to a string that remains accessible.
   explicit VideoContentCaptureSourceSelectionResult(
       const char* failed_constraint_name);
 
-  // Creates a result with the given values. |device_id| is moved to an internal
-  // field.
+  // Creates a result with the given values.
   VideoContentCaptureSourceSelectionResult(
       std::string device_id,
       const rtc::Optional<bool>& noise_reduction,
       media::VideoCaptureParams capture_params);
 
   VideoContentCaptureSourceSelectionResult(
       const VideoContentCaptureSourceSelectionResult& other);
   VideoContentCaptureSourceSelectionResult& operator=(
       const VideoContentCaptureSourceSelectionResult& other);
   VideoContentCaptureSourceSelectionResult(
@@ skipping 34 matching lines @@
 
 // This function performs source and source-settings selection for content
 // video capture based on the given |constraints|.
 VideoContentCaptureSourceSelectionResult CONTENT_EXPORT
 SelectVideoContentCaptureSourceSettings(
     const blink::WebMediaConstraints& constraints);
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_CONSTRAINTS_UTIL_VIDEO_CONTENT_H_