Remove DeviceMonitorLinux::WillDestroyCurrentMessageLoop().

extensions/shell/browser/shell_device_client.h

Index: extensions/shell/browser/shell_device_client.h
diff --git a/extensions/shell/browser/shell_device_client.h b/extensions/shell/browser/shell_device_client.h
index ae4bac1b513b646cfda4310e031f6c85c78b7b8e..8a01bc8b6ec53ee70f1b0ef46e7199102e4d00f8 100644
--- a/extensions/shell/browser/shell_device_client.h
+++ b/extensions/shell/browser/shell_device_client.h
@@ -7,7 +7,7 @@
 
 #include <memory>
 
-#include "base/compiler_specific.h"
+#include "base/logging.h"
 #include "base/macros.h"
 #include "device/base/device_client.h"
 
@@ -20,11 +20,18 @@ class ShellDeviceClient : device::DeviceClient {
   ShellDeviceClient();
   ~ShellDeviceClient() override;
 
+  // Must be called before the destructor, when the FILE thread is still alive.
+  void Shutdown();
+
   // device::DeviceClient implementation
   device::UsbService* GetUsbService() override;
   device::HidService* GetHidService() override;
 
  private:
+#if DCHECK_IS_ON()
+  bool did_shutdown_ = false;
+#endif
+
   std::unique_ptr<device::HidService> hid_service_;
   std::unique_ptr<device::UsbService> usb_service_;