Add logging for debugging screen capture notification window not excluded on Mac.

BUG=414362

Review URL: https://codereview.chromium.org/576543003

Cr-Commit-Position: refs/heads/master@{#294977}

content/browser/renderer_host/media/video_capture_manager.cc

@@ -263,6 +263,8 @@ void VideoCaptureManager::DoStartDeviceOnDeviceThread(
             notification_window_ids_.end()) {
           static_cast<DesktopCaptureDevice*>(video_capture_device.get())
               ->SetNotificationWindowId(notification_window_ids_[session_id]);
+          VLOG(2) << "Screen capture notification window passed for session "
+                  << session_id;
         }
       }
 #endif  // defined(ENABLE_SCREEN_CAPTURE)
@@ -410,8 +412,11 @@ void VideoCaptureManager::SetDesktopCaptureWindowId(
     media::VideoCaptureSessionId session_id,
     gfx::NativeViewId window_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  VLOG(2) << "SetDesktopCaptureWindowId called for session " << session_id;
+
   SessionMap::iterator session_it = sessions_.find(session_id);
   if (session_it == sessions_.end()) {
+    VLOG(2) << "Session not found, will save the notification window.";
     device_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(
@@ -424,13 +429,16 @@ void VideoCaptureManager::SetDesktopCaptureWindowId(
 
   DeviceEntry* const existing_device =
       GetDeviceEntryForMediaStreamDevice(session_it->second);
-  if (!existing_device)
+  if (!existing_device) {
+    VLOG(2) << "Failed to find an existing device.";
     return;
+  }
 
   DCHECK_EQ(MEDIA_DESKTOP_VIDEO_CAPTURE, existing_device->stream_type);
   DesktopMediaID id = DesktopMediaID::Parse(existing_device->id);
   if (id.type == DesktopMediaID::TYPE_NONE ||
       id.type == DesktopMediaID::TYPE_AURA_WINDOW) {
+    VLOG(2) << "Video capture device type mismatch.";
     return;
   }
 
@@ -640,6 +648,7 @@ void VideoCaptureManager::SetDesktopCaptureWindowIdOnDeviceThread(
   DesktopCaptureDevice* device =
       static_cast<DesktopCaptureDevice*>(entry->video_capture_device.get());
   device->SetNotificationWindowId(window_id);
+  VLOG(2) << "Screen capture notification window passed on device thread.";
 #endif
 }
 
@@ -650,6 +659,8 @@ void VideoCaptureManager::SaveDesktopCaptureWindowIdOnDeviceThread(
   DCHECK(notification_window_ids_.find(session_id) ==
          notification_window_ids_.end());
   notification_window_ids_[session_id] = window_id;
+  VLOG(2) << "Screen capture notification window saved for session "
+          << session_id << " on device thread.";
 }
 
 }  // namespace content