Abort SandboxedUnpacker::RewriteImageFiles on browser shutdown

base/threading/sequenced_worker_pool.h

 // Copyright (c) 2012 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 BASE_THREADING_SEQUENCED_WORKER_POOL_H_
 #define BASE_THREADING_SEQUENCED_WORKER_POOL_H_
 
 #include <cstddef>
 #include <string>
 
@@ skipping 298 matching lines @@
 
   // A variant that allows an arbitrary number of new blocking tasks to
   // be posted during shutdown from within tasks that execute during shutdown.
   // Only tasks designated as BLOCKING_SHUTDOWN will be allowed, and only if
   // posted by tasks that are not designated as CONTINUE_ON_SHUTDOWN. Once
   // the limit is reached, subsequent calls to post task fail in all cases.
   //
   // Must be called from the same thread this object was constructed on.
   void Shutdown(int max_new_blocking_tasks_after_shutdown);
 
+  // Check if Shutdown was called for given threading pool. This method is used
+  // for aborting time consuming operation to avoid blocking shutdown.
+  //
+  // Can be called from any thread.
+  bool IsShutdownInProgress();
+
  protected:
   virtual ~SequencedWorkerPool();
 
   virtual void OnDestruct() const OVERRIDE;
 
  private:
   friend class RefCountedThreadSafe<SequencedWorkerPool>;
   friend class DeleteHelper<SequencedWorkerPool>;
 
   class Inner;
   class Worker;
 
   const scoped_refptr<MessageLoopProxy> constructor_message_loop_;
 
   // Avoid pulling in too many headers by putting (almost) everything
   // into |inner_|.
   const scoped_ptr<Inner> inner_;
 
   DISALLOW_COPY_AND_ASSIGN(SequencedWorkerPool);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_SEQUENCED_WORKER_POOL_H_