DevTools: Fix a DCHECK failure during browser shutdown.

chrome/browser/devtools/device/port_forwarding_controller.cc

Index: chrome/browser/devtools/device/port_forwarding_controller.cc
diff --git a/chrome/browser/devtools/device/port_forwarding_controller.cc b/chrome/browser/devtools/device/port_forwarding_controller.cc
index b6338e2632d9c8bb1a81024895823c6ec6b3c672..937aa3477ff286dbb5e659aa860d33f0640dc07c 100644
--- a/chrome/browser/devtools/device/port_forwarding_controller.cc
+++ b/chrome/browser/devtools/device/port_forwarding_controller.cc
@@ -535,7 +535,10 @@ PortForwardingController::PortForwardingController(Profile* profile)
   OnPrefsChange();
 }
 
-PortForwardingController::~PortForwardingController() {
+
+PortForwardingController::~PortForwardingController() {}
+
+void PortForwardingController::Shutdown() {
   // Existing connection will not be shut down. This might be confusing for
   // some users, but the opposite is more confusing.
   StopListening();