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..b6eefdca46210bef6994b6bf795b688c7a848432 100644
--- a/media/capture/video/mac/video_capture_device_decklink_mac.mm
+++ b/media/capture/video/mac/video_capture_device_decklink_mac.mm
@@ -98,6 +98,8 @@ class DeckLinkCaptureDelegate
   // Checks for Device (a.k.a. Audio) thread.
   base::ThreadChecker thread_checker_;
 
+  bool capture_;
+
   friend class scoped_refptr<DeckLinkCaptureDelegate>;
   friend class base::RefCountedThreadSafe<DeckLinkCaptureDelegate>;
 
@@ -126,7 +128,9 @@ static float GetDisplayModeFrameRate(
 DeckLinkCaptureDelegate::DeckLinkCaptureDelegate(
     const media::VideoCaptureDeviceDescriptor& device_descriptor,
     media::VideoCaptureDeviceDeckLinkMac* frame_receiver)
-    : device_descriptor_(device_descriptor), frame_receiver_(frame_receiver) {}
+    : device_descriptor_(device_descriptor),
+      frame_receiver_(frame_receiver),
+      capture_(false) {}
 
 DeckLinkCaptureDelegate::~DeckLinkCaptureDelegate() {
 }
@@ -209,12 +213,18 @@ void DeckLinkCaptureDelegate::AllocateAndStart(
   if (decklink_input_local->StartStreams() != S_OK)
     SendErrorString(FROM_HERE, "Could not start capturing");
 
+  if (frame_receiver_)
+    frame_receiver_->ReportStarted();
+
+  capture_ = true;
+
   decklink_.swap(decklink_local);
   decklink_input_.swap(decklink_input_local);
 }
 
 void DeckLinkCaptureDelegate::StopAndDeAllocate() {
   DCHECK(thread_checker_.CalledOnValidThread());
+  capture_ = false;
   if (!decklink_input_.get())
     return;
   if (decklink_input_->StopStreams() != S_OK)
@@ -237,6 +247,9 @@ HRESULT DeckLinkCaptureDelegate::VideoInputFormatChanged(
 HRESULT DeckLinkCaptureDelegate::VideoInputFrameArrived(
     IDeckLinkVideoInputFrame* video_frame,
     IDeckLinkAudioInputPacket* /* audio_packet */) {
+  if (!capture_)
+    return S_OK;
+
   // Capture frames are manipulated as an IDeckLinkVideoFrame.
   uint8_t* video_data = NULL;
   video_frame->GetBytes(reinterpret_cast<void**>(&video_data));
@@ -494,6 +507,13 @@ 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) {