Observed in CI: https://app.circleci.com/pipelines/github/electron/electron/30672/workflows/69ab6601-3698-411b-8906-93c9aca28870/jobs/675633

```
Received signal 11 SEGV_MAPERR 000000000048
0   Electron Framework                  0x0000000116967079 base::debug::CollectStackTrace(void**, unsigned long) + 9
1   Electron Framework                  0x0000000116861a13 base::debug::StackTrace::StackTrace() + 19
2   Electron Framework                  0x0000000116966f41 base::debug::(anonymous namespace)::StackDumpSignalHandler(int, __siginfo*, void*) + 2385
3   libsystem_platform.dylib            0x00007fff68c005fd _sigtramp + 29
4   ???                                 0x00000001026a2a00 0x0 + 4335479296
5   Electron Framework                  0x0000000111155798 base::ObserverList<content::SerialDelegate::Observer, false, true, base::internal::CheckedObserverAdapter>::RemoveObserver(content::SerialDelegate::Observer const*) + 104
6   Electron Framework                  0x0000000111158b20 electron::SerialChooserController::~SerialChooserController() + 256
7   Electron Framework                  0x00000001111535fc electron::ElectronSerialDelegate::~ElectronSerialDelegate() + 124
8   Electron Framework                  0x00000001110ed524 electron::ElectronBrowserClient::~ElectronBrowserClient() + 132
9   Electron Framework                  0x00000001110ed5ee electron::ElectronBrowserClient::~ElectronBrowserClient() + 14
10  Electron Framework                  0x0000000110fdbde7 ElectronMain + 151
```
shell/browser/serial/serial_chooser_controller.h
#ifndef SHELL_BROWSER_SERIAL_SERIAL_CHOOSER_CONTROLLER_H_
#define SHELL_BROWSER_SERIAL_SERIAL_CHOOSER_CONTROLLER_H_
#include <string>
#include <vector>
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/scoped_observer.h"
#include "base/strings/string16.h"
#include "content/public/browser/serial_chooser.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_observer.h"
#include "services/device/public/mojom/serial.mojom-forward.h"
#include "shell/browser/api/electron_api_session.h"
#include "shell/browser/serial/electron_serial_delegate.h"
#include "shell/browser/serial/serial_chooser_context.h"
#include "third_party/blink/public/mojom/serial/serial.mojom.h"
namespace content {
class RenderFrameHost;
}  
namespace electron {
class ElectronSerialDelegate;
class SerialChooserController final : public SerialChooserContext::PortObserver,
                                      public content::WebContentsObserver {
 public:
  SerialChooserController(
      content::RenderFrameHost* render_frame_host,
      std::vector<blink::mojom::SerialPortFilterPtr> filters,
      content::SerialChooser::Callback callback,
      content::WebContents* web_contents,