VideoCaptureImpl cleanup: merge ctor+Init() and DeInit()+dtor.

content/renderer/media/video_capture_impl.cc

Index: content/renderer/media/video_capture_impl.cc
diff --git a/content/renderer/media/video_capture_impl.cc b/content/renderer/media/video_capture_impl.cc
index 43d59930d052fecb3d8a48834a2b76c55e060d7e..583fb97bb9e68b9fffc02977cecb96879447632e 100644
--- a/content/renderer/media/video_capture_impl.cc
+++ b/content/renderer/media/video_capture_impl.cc
@@ -105,33 +105,24 @@ VideoCaptureImpl::ClientInfo::ClientInfo(const ClientInfo& other) = default;
 VideoCaptureImpl::ClientInfo::~ClientInfo() {}
 
 VideoCaptureImpl::VideoCaptureImpl(
-    const media::VideoCaptureSessionId session_id,
-    VideoCaptureMessageFilter* filter)
+    media::VideoCaptureSessionId session_id,
+    VideoCaptureMessageFilter* filter,
+    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner)
     : message_filter_(filter),
       device_id_(0),
       session_id_(session_id),
       suspended_(false),
       state_(VIDEO_CAPTURE_STATE_STOPPED),
+      io_task_runner_(std::move(io_task_runner)),
       weak_factory_(this) {
   DCHECK(filter);
+  io_task_runner_->PostTask(FROM_HERE,
+                            base::Bind(&VideoCaptureMessageFilter::AddDelegate,
+                                       message_filter_, this));
 }
 
 VideoCaptureImpl::~VideoCaptureImpl() {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
-}
-
-void VideoCaptureImpl::Init() {
-  // For creating callbacks in unittest, this class may be constructed from a
-  // different thread than the IO thread, e.g. wherever unittest runs on.
-  // Therefore, this function should define the thread ownership.
-#if DCHECK_IS_ON()
-  io_task_runner_ = base::ThreadTaskRunnerHandle::Get();
-#endif
-  message_filter_->AddDelegate(this);
-}
-
-void VideoCaptureImpl::DeInit() {
-  DCHECK(io_task_runner_->BelongsToCurrentThread());
   if (state_ == VIDEO_CAPTURE_STATE_STARTED)
     Send(new VideoCaptureHostMsg_Stop(device_id_));
   message_filter_->RemoveDelegate(this);