[CacheStorage] Fix a failed cache migration issue

content/browser/cache_storage/cache_storage.cc

 // Copyright 2014 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 "content/browser/cache_storage/cache_storage.h"
 
 #include <set>
 #include <string>
 
 #include "base/barrier_closure.h"
@@ skipping 383 matching lines @@
           cache_path = origin_path.AppendASCII(cache_dir);
         } while (base::PathExists(cache_path));
 
         if (!base::Move(legacy_cache_path, cache_path)) {
           // If the move fails then the cache is in a bad state. Return an empty
           // index so that the CacheStorage can start fresh. The unreferenced
           // caches will be discarded later in initialization.
           return kBadIndexState;
         }
 
-        index.mutable_cache(0)->set_cache_dir(cache_dir);
+        index.mutable_cache(i)->set_cache_dir(cache_dir);
         index_is_dirty = true;
       }
     }
 
     if (index_is_dirty) {
       std::string new_body;
       if (!index.SerializeToString(&new_body))
         return kBadIndexState;
       if (base::WriteFile(index_path, new_body.c_str(), new_body.size()) !=
           base::checked_cast<int>(new_body.size()))
@@ skipping 519 matching lines @@
     scoped_ptr<ServiceWorkerResponse> response,
     scoped_ptr<storage::BlobDataHandle> blob_data_handle) {
   base::WeakPtr<CacheStorage> cache_storage = weak_factory_.GetWeakPtr();
 
   callback.Run(error, response.Pass(), blob_data_handle.Pass());
   if (cache_storage)
     scheduler_->CompleteOperationAndRunNext();
 }
 
 }  // namespace content