Explicitly check various sync_file_system classes live on the IO thread.

chrome/browser/sync_file_system/local/syncable_file_operation_runner.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_
 
 #include <stdint.h>
 
 #include <list>
 #include <memory>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/non_thread_safe.h"
 #include "chrome/browser/sync_file_system/local/local_file_sync_status.h"
 #include "storage/browser/fileapi/file_system_url.h"
 
 namespace storage {
 class FileSystemURL;
 }
 
 namespace sync_file_system {
 
 // This class must run only on IO thread.
 // Owned by LocalFileSyncContext.
 class SyncableFileOperationRunner
-    : public base::NonThreadSafe,
-      public base::SupportsWeakPtr<SyncableFileOperationRunner>,
+    : public base::SupportsWeakPtr<SyncableFileOperationRunner>,
       public LocalFileSyncStatus::Observer {
  public:
   // Represents an operation task (which usually wraps one FileSystemOperation).
   class Task {
    public:
     Task() {}
     virtual ~Task() {}
 
     // Only one of Run() or Cancel() is called.
     virtual void Run() = 0;
     virtual void Cancel() = 0;
 
    protected:
     // This is never called after Run() or Cancel() is called.
     virtual const std::vector<storage::FileSystemURL>& target_paths() const = 0;
 
    private:
     friend class SyncableFileOperationRunner;
     bool IsRunnable(LocalFileSyncStatus* status) const;
     void Start(LocalFileSyncStatus* status);
-    static void CancelAndDelete(Task* task);
 
     DISALLOW_COPY_AND_ASSIGN(Task);
   };
 
   SyncableFileOperationRunner(int64_t max_inflight_tasks,
                               LocalFileSyncStatus* sync_status);
   ~SyncableFileOperationRunner() override;
 
   // LocalFileSyncStatus::Observer overrides.
   void OnSyncEnabled(const storage::FileSystemURL& url) override;
@@ skipping 21 matching lines @@
     return static_cast<int64_t>(pending_tasks_.size());
   }
 
   int64_t num_inflight_tasks() const { return num_inflight_tasks_; }
 
  private:
   // Returns true if we should start more tasks.
   bool ShouldStartMoreTasks() const;
 
   // Keeps track of the writing/syncing status. Not owned.
-  LocalFileSyncStatus* sync_status_;
+  LocalFileSyncStatus* const sync_status_;
 
-  std::list<Task*> pending_tasks_;
+  std::list<std::unique_ptr<Task>> pending_tasks_;
 
   const int64_t max_inflight_tasks_;
   int64_t num_inflight_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncableFileOperationRunner);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_