Split FakeVideoCaptureDevice into classes with single responsibility

media/capture/video/fake_video_capture_device_factory.h

 // Copyright 2014 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.
 
-// Implementation of a fake VideoCaptureDeviceFactory class.
-
 #ifndef MEDIA_CAPTURE_VIDEO_FAKE_VIDEO_CAPTURE_DEVICE_FACTORY_H_
 #define MEDIA_CAPTURE_VIDEO_FAKE_VIDEO_CAPTURE_DEVICE_FACTORY_H_
 
 #include "media/capture/video/fake_video_capture_device.h"
 #include "media/capture/video/video_capture_device_factory.h"
 
 namespace media {
 
-// Extension of VideoCaptureDeviceFactory to create and manipulate fake devices,
-// not including file-based ones.
+// Implementation of VideoCaptureDeviceFactory that creates fake devices
+// that generate test output frames.
+// By default, the factory has one device outputting I420.
+// When increasing the number of devices using set_number_of_devices(), the
+// second device will use Y16, and any devices beyond that will use I420.
+// By default, the delivery mode of all devices is USE_OWN_BUFFERS.
+// This, as well as other parameters, can be changed using command-line flags.
+// See implementation of method ParseCommandLine() for details.
 class CAPTURE_EXPORT FakeVideoCaptureDeviceFactory
     : public VideoCaptureDeviceFactory {
  public:
   FakeVideoCaptureDeviceFactory();
   ~FakeVideoCaptureDeviceFactory() override {}
 
   std::unique_ptr<VideoCaptureDevice> CreateDevice(
       const VideoCaptureDeviceDescriptor& device_descriptor) override;
   void GetDeviceDescriptors(
       VideoCaptureDeviceDescriptors* device_descriptors) override;
   void GetSupportedFormats(
       const VideoCaptureDeviceDescriptor& device_descriptor,
       VideoCaptureFormats* supported_formats) override;
 
   void set_number_of_devices(int number_of_devices) {
     DCHECK(thread_checker_.CalledOnValidThread());
     number_of_devices_ = number_of_devices;
   }
   int number_of_devices() {
     DCHECK(thread_checker_.CalledOnValidThread());
     return number_of_devices_;
   }
 
  private:
   void ParseCommandLine();
 
   int number_of_devices_;
-  FakeVideoCaptureDevice::BufferOwnership fake_vcd_ownership_;
+  FakeVideoCaptureDeviceMaker::DeliveryMode delivery_mode_;
   float frame_rate_;
   bool command_line_parsed_ = false;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_FAKE_VIDEO_CAPTURE_DEVICE_FACTORY_H_