indexeddb: Removed use of dangling ptr in writeBlobToFileOnIOThread.

content/browser/indexed_db/indexed_db_backing_store.h

 // Copyright (c) 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 CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_
 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 441 matching lines @@
 
      private:
       bool is_file_;
       GURL url_;
       base::FilePath file_path_;
       int64_t key_;
       int64_t size_;
       base::Time last_modified_;
     };
 
-    class ChainedBlobWriter : public base::RefCounted<ChainedBlobWriter> {
+    class ChainedBlobWriter
+        : public base::RefCountedThreadSafe<ChainedBlobWriter> {
      public:
       virtual void set_delegate(
           scoped_ptr<fileapi::FileWriterDelegate> delegate) = 0;
 
       // TODO(ericu): Add a reason in the event of failure.
       virtual void ReportWriteCompletion(bool succeeded,
                                          int64 bytes_written) = 0;
 
       virtual void Abort() = 0;
 
      protected:
       virtual ~ChainedBlobWriter() {}
-      friend class base::RefCounted<ChainedBlobWriter>;
+      friend class base::RefCountedThreadSafe<ChainedBlobWriter>;

[michaeln1, 2014/07/23 20:15:15]

style nit: ditto 

     };
 
     class ChainedBlobWriterImpl;
 
     typedef std::vector<WriteDescriptor> WriteDescriptorVec;
 
    private:
     class BlobWriteCallbackWrapper;
 
     leveldb::Status HandleBlobPreTransaction(
@@ skipping 93 matching lines @@
   // will hold a reference to this backing store.
   IndexedDBActiveBlobRegistry active_blob_registry_;
   base::OneShotTimer<IndexedDBBackingStore> close_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(IndexedDBBackingStore);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_