Revert of [Mojo Video Capture] Introduce abstraction VideoCaptureSystem

media/capture/video/video_capture_system.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 MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_SYSTEM_H_
-#define MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_SYSTEM_H_
-
-#include "media/capture/video/video_capture_device_factory.h"
-#include "media/capture/video/video_capture_device_info.h"
-
-namespace media {
-
-// Layer on top of VideoCaptureDeviceFactory that translates device descriptors
-// to string identifiers and consolidates and caches device descriptors and
-// supported formats into VideoCaptureDeviceInfos.
-class CAPTURE_EXPORT VideoCaptureSystem {
- public:
-  using DeviceInfoCallback =
-      base::Callback<void(const std::vector<VideoCaptureDeviceInfo>&)>;
-
-  explicit VideoCaptureSystem(
-      std::unique_ptr<VideoCaptureDeviceFactory> factory);
-  ~VideoCaptureSystem();
-
-  // The passed-in |result_callback| must have ownership of the called
-  // VideoCaptureSystem instance to guarantee that it stays alive during the
-  // asynchronous operation.
-  void GetDeviceInfosAsync(const DeviceInfoCallback& result_callback);
-
-  // Creates a VideoCaptureDevice object. Returns nullptr if something goes
-  // wrong.
-  std::unique_ptr<VideoCaptureDevice> CreateDevice(
-      const std::string& device_id);
-
-  media::VideoCaptureDeviceFactory* video_capture_device_factory() const {
-    return factory_.get();
-  }
-
- private:
-  void OnDescriptorsReceived(
-      const DeviceInfoCallback& result_callback,
-      std::unique_ptr<VideoCaptureDeviceDescriptors> descriptors);
-
-  // Returns nullptr if no descriptor found.
-  const VideoCaptureDeviceInfo* LookupDeviceInfoFromId(
-      const std::string& device_id);
-
-  const std::unique_ptr<VideoCaptureDeviceFactory> factory_;
-  std::vector<VideoCaptureDeviceInfo> devices_info_cache_;
-
-  base::ThreadChecker thread_checker_;
-};
-
-}  // namespace media
-
-#endif  // MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_