exo: Fix crash in out-of-order destruction of Gamepad

components/exo/gamepad.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/exo/gamepad.h"
 
 #include <cmath>
 
 #include "ash/shell.h"
 #include "base/bind.h"
@@ skipping 36 matching lines @@
 class Gamepad::ThreadSafeGamepadChangeFetcher
     : public base::RefCountedThreadSafe<
           Gamepad::ThreadSafeGamepadChangeFetcher> {
  public:
   using ProcessGamepadChangesCallback =
       base::Callback<void(const blink::WebGamepad)>;
 
   ThreadSafeGamepadChangeFetcher(
       const ProcessGamepadChangesCallback& post_gamepad_changes,
       const CreateGamepadDataFetcherCallback& create_fetcher_callback,
-      base::SingleThreadTaskRunner* task_runner)
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner)
       : process_gamepad_changes_(post_gamepad_changes),
         create_fetcher_callback_(create_fetcher_callback),
         polling_task_runner_(task_runner),
         origin_task_runner_(base::ThreadTaskRunnerHandle::Get()) {
     thread_checker_.DetachFromThread();
   }
 
   // Enable or disable gamepad polling. Can be called from any thread.
   void EnablePolling(bool enabled) {
     polling_task_runner_->PostTask(
@@ skipping 66 matching lines @@
     SchedulePollOnPollingThread();
   }
 
   // Callback to ProcessGamepadChanges using weak reference to Gamepad.
   ProcessGamepadChangesCallback process_gamepad_changes_;
 
   // Callback method to create a gamepad data fetcher.
   CreateGamepadDataFetcherCallback create_fetcher_callback_;
 
   // Reference to task runner on polling thread.
-  base::SingleThreadTaskRunner* polling_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> polling_task_runner_;
 
   // Reference to task runner on origin thread.
   scoped_refptr<base::SingleThreadTaskRunner> origin_task_runner_;
 
   // Gamepad data fetcher used for querying gamepad devices.
   std::unique_ptr<device::GamepadDataFetcher> fetcher_;
 
   // The current state of all gamepads.
   blink::WebGamepads state_;
 
   // True if a poll has been scheduled.
   bool has_poll_scheduled_ = false;
 
   // True if the polling thread is paused.
   bool is_enabled_ = false;
 
   // ThreadChecker for the polling thread.
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadSafeGamepadChangeFetcher);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // Gamepad, public:
 
-Gamepad::Gamepad(GamepadDelegate* delegate,
-                 base::SingleThreadTaskRunner* polling_task_runner)
+Gamepad::Gamepad(
+    GamepadDelegate* delegate,
+    scoped_refptr<base::SingleThreadTaskRunner> polling_task_runner)
     : Gamepad(delegate,
               polling_task_runner,
               base::Bind(CreateGamepadPlatformDataFetcher)) {}
 
-Gamepad::Gamepad(GamepadDelegate* delegate,
-                 base::SingleThreadTaskRunner* polling_task_runner,
-                 CreateGamepadDataFetcherCallback create_fetcher_callback)
+Gamepad::Gamepad(
+    GamepadDelegate* delegate,
+    scoped_refptr<base::SingleThreadTaskRunner> polling_task_runner,
+    CreateGamepadDataFetcherCallback create_fetcher_callback)
     : delegate_(delegate), weak_factory_(this) {
   gamepad_change_fetcher_ = new ThreadSafeGamepadChangeFetcher(
       base::Bind(&Gamepad::ProcessGamepadChanges, weak_factory_.GetWeakPtr()),
       create_fetcher_callback, polling_task_runner);
 
   aura::client::FocusClient* focus_client =
       aura::client::GetFocusClient(ash::Shell::GetPrimaryRootWindow());
   focus_client->AddObserver(this);
   OnWindowFocused(focus_client->GetFocusedWindow(), nullptr);
 }
@@ skipping 67 matching lines @@
       delegate_->OnButton(button_id, new_button.pressed, new_button.value);
     }
   }
   if (send_frame)
     delegate_->OnFrame();
 
   pad_state_ = new_pad;
 }
 
 }  // namespace exo