getUserMeida: report device starting states

media/capture/video/mac/video_capture_device_decklink_mac.mm

Index: media/capture/video/mac/video_capture_device_decklink_mac.mm
diff --git a/media/capture/video/mac/video_capture_device_decklink_mac.mm b/media/capture/video/mac/video_capture_device_decklink_mac.mm
index 54bb0ccde568fb563bbc9f8faffed7bc44c8fa1f..6948165f5f9bd15b8d1ac8776d958273bb02590f 100644
--- a/media/capture/video/mac/video_capture_device_decklink_mac.mm
+++ b/media/capture/video/mac/video_capture_device_decklink_mac.mm
@@ -209,6 +209,9 @@ void DeckLinkCaptureDelegate::AllocateAndStart(
   if (decklink_input_local->StartStreams() != S_OK)
     SendErrorString(FROM_HERE, "Could not start capturing");
 
+  if (frame_receiver_)
+    frame_receiver_->ReportStarted();
+
   decklink_.swap(decklink_local);
   decklink_input_.swap(decklink_input_local);
 }
@@ -494,6 +497,13 @@ void VideoCaptureDeviceDeckLinkMac::SendLogString(const std::string& message) {
     client_->OnLog(message);
 }
 
+void VideoCaptureDeviceDeckLinkMac::ReportStarted() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  base::AutoLock lock(lock_);
+  if (client_)
+    client_->OnStarted();
+}
+
 void VideoCaptureDeviceDeckLinkMac::AllocateAndStart(
     const VideoCaptureParams& params,
     std::unique_ptr<VideoCaptureDevice::Client> client) {