Shutdown StoragePartition before ProfileIOData is being shut down

content/browser/storage_partition_impl.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 CONTENT_BROWSER_STORAGE_PARTITION_IMPL_H_
 #define CONTENT_BROWSER_STORAGE_PARTITION_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
@@ skipping 16 matching lines @@
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "net/cookies/cookie_store.h"
 #include "storage/browser/quota/special_storage_policy.h"
 
 namespace content {
 
 class CONTENT_EXPORT  StoragePartitionImpl
     : public StoragePartition,
       public NON_EXPORTED_BASE(mojom::StoragePartitionService) {
  public:
+  // It is guaranteed that storage partitions are destructed before the
+  // browser context starts shutting down its corresponding IO thread residents
+  // (e.g. resource context).
   ~StoragePartitionImpl() override;
 
   // Quota managed data uses a different bitmask for types than
   // StoragePartition uses. This method generates that mask.
   static int GenerateQuotaClientMask(uint32_t remove_mask);
 
   // This creates a CookiePredicate that matches all host (NOT domain) cookies
   // that match the host of |url|. This is intended to be used with
   // DeleteAllCreatedBetweenWithPredicateAsync.
   static net::CookieStore::CookiePredicate
@@ skipping 180 matching lines @@
   // StoragePartitionImplMap which then owns StoragePartitionImpl. When the
   // BrowserContext is destroyed, |this| will be destroyed too.
   BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(StoragePartitionImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_STORAGE_PARTITION_IMPL_H_