[Mojo Video Capture] Fix VideoCaptureManager exposing implementation details to clients

content/browser/renderer_host/media/media_stream_manager.h

 // Copyright (c) 2012 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.
 
 // MediaStreamManager is used to open media capture devices (video supported
 // now). Call flow:
 // 1. GenerateStream is called when a render process wants to use a capture
 //    device.
 // 2. MediaStreamManager will ask MediaStreamUIController for permission to
 //    use devices and for which device to use.
@@ skipping 31 matching lines @@
 #include "content/browser/renderer_host/media/media_devices_manager.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_devices.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/browser/media_request_state.h"
 #include "media/base/video_facing.h"
 
 namespace media {
 class AudioSystem;
+class VideoCaptureSystem;
 }
 
 namespace url {
 class Origin;
 }
 
 namespace content {
 
 class AudioInputDeviceManager;
 class FakeMediaStreamUIProxy;
@@ skipping 16 matching lines @@
 
   // Callback for testing.
   typedef base::Callback<bool(const StreamControls&)>
       GenerateStreamTestCallback;
 
   // Adds |message| to native logs for outstanding device requests, for use by
   // render processes hosts whose corresponding render processes are requesting
   // logging from webrtcLoggingPrivate API. Safe to call from any thread.
   static void SendMessageToNativeLog(const std::string& message);
 
-  explicit MediaStreamManager(media::AudioSystem* audio_system);
+  static std::unique_ptr<MediaStreamManager> CreateWithDefaults(

[miu, 2017/04/03 21:31:23]

Perhaps include a comment about threading/task-runners to be assumed here?

[chfremer, 2017/04/04 21:59:32]

I wouldn't know what to say here. As a reader, what kind of information would
you be looking for here that would not have been given in the class-level
description?

I don't feel I understand the class MediaStreamManager enough to attempt
explaining it in a class-level comment.

+      media::AudioSystem* audio_system);
+
+  static std::unique_ptr<MediaStreamManager>
+  CreateWithCustomVideoCaptureDeviceTaskRunner(

[miu, 2017/04/03 21:31:23]

Looks like nothing calls this. So, can we delete it?

[chfremer, 2017/04/04 21:59:32]

Done.

+      media::AudioSystem* audio_system,
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+
+  static std::unique_ptr<MediaStreamManager> CreateWithCustomVideoCaptureSystem(
+      media::AudioSystem* audio_system,
+      std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
 
   ~MediaStreamManager() override;
 
   // Used to access VideoCaptureManager.
   VideoCaptureManager* video_capture_manager();
 
   // Used to access AudioInputDeviceManager.
   AudioInputDeviceManager* audio_input_device_manager();
 
   // Used to access MediaDevicesManager.
@@ skipping 171 matching lines @@
  private:
   // Contains all data needed to keep track of requests.
   class DeviceRequest;
 
   // |DeviceRequests| is a list to ensure requests are processed in the order
   // they arrive. The first member of the pair is the label of the
   // |DeviceRequest|.
   using LabeledDeviceRequest = std::pair<std::string, DeviceRequest*>;
   using DeviceRequests = std::list<LabeledDeviceRequest>;
 
-  // Initializes the device managers on IO thread.  Auto-starts the device
-  // thread and registers this as a listener with the device managers.
-  void InitializeDeviceManagersOnIOThread();
+  explicit MediaStreamManager(media::AudioSystem* audio_system);
+  void InitializeWithDefaults();
+  void InitializeWithCustomVideoCaptureDeviceTaskRunner(
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+  void InitializeWithCustomVideoCaptureSystem(
+      std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+  void PerformCommonInitializationRoutines();
 
   // |output_parameters| contains real values only if the request requires it.
   void HandleAccessRequestResponse(
       const std::string& label,
       const media::AudioParameters& output_parameters,
       const MediaStreamDevices& devices,
       content::MediaStreamRequestResult result);
   void StopMediaStreamFromBrowser(const std::string& label);
 
   // Helpers.
@@ skipping 130 matching lines @@
   std::map<int, base::Callback<void(const std::string&)>> log_callbacks_;
 
   GenerateStreamTestCallback generate_stream_test_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_MANAGER_H_