Fix for ~ContentCaptureSubscription() after BrowserThreads are torn down.

content/browser/media/capture/desktop_capture_device_aura.cc

Index: content/browser/media/capture/desktop_capture_device_aura.cc
diff --git a/content/browser/media/capture/desktop_capture_device_aura.cc b/content/browser/media/capture/desktop_capture_device_aura.cc
index 14dc780f19cb03789ed7d87e33944ecacbd6d7b6..8cc0688d251cf3b8be624ad4e1ed035878c83eb9 100644
--- a/content/browser/media/capture/desktop_capture_device_aura.cc
+++ b/content/browser/media/capture/desktop_capture_device_aura.cc
@@ -227,7 +227,6 @@ bool DesktopVideoCaptureMachine::Start(
                base::Bind(&DesktopVideoCaptureMachine::Capture, AsWeakPtr(),
                           false));
 
-  started_ = true;
   return true;
 }
 
@@ -246,8 +245,6 @@ void DesktopVideoCaptureMachine::Stop(const base::Closure& callback) {
   // Stop timer.
   timer_.Stop();
 
-  started_ = false;
-
   callback.Run();
 }