src/content/browser/indexed_db/indexed_db_backing_store.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_
   6 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_
   7
   8 #include <map>
   9 #include <set>
  10 #include <string>
  11 #include <utility>
  12 #include <vector>
  13
  14 #include "base/basictypes.h"
  15 #include "base/files/file_path.h"
  16 #include "base/memory/ref_counted.h"
  17 #include "base/memory/scoped_ptr.h"
  18 #include "base/strings/string_piece.h"
  19 #include "base/time/time.h"
  20 #include "base/timer/timer.h"
  21 #include "content/browser/indexed_db/indexed_db.h"
  22 #include "content/browser/indexed_db/indexed_db_active_blob_registry.h"
  23 #include "content/browser/indexed_db/indexed_db_blob_info.h"
  24 #include "content/browser/indexed_db/indexed_db_leveldb_coding.h"
  25 #include "content/browser/indexed_db/indexed_db_metadata.h"
  26 #include "content/browser/indexed_db/leveldb/leveldb_iterator.h"
  27 #include "content/browser/indexed_db/leveldb/leveldb_transaction.h"
  28 #include "content/common/content_export.h"
  29 #include "content/common/indexed_db/indexed_db_key.h"
  30 #include "content/common/indexed_db/indexed_db_key_path.h"
  31 #include "content/common/indexed_db/indexed_db_key_range.h"
  32 #include "storage/browser/blob/blob_data_handle.h"
  33 #include "third_party/leveldatabase/src/include/leveldb/status.h"
  34 #include "url/gurl.h"
  35
  36 namespace base {
  37 class SequencedTaskRunner;
  38 }
  39
  40 namespace storage {
  41 class FileWriterDelegate;
  42 }
  43
  44 namespace net {
  45 class URLRequestContext;
  46 }
  47
  48 namespace content {
  49
  50 class IndexedDBFactory;
  51 class LevelDBComparator;
  52 class LevelDBDatabase;
  53 class LevelDBFactory;
  54 struct IndexedDBValue;
  55
  56 class CONTENT_EXPORT IndexedDBBackingStore
  57     : public base::RefCounted<IndexedDBBackingStore> {
  58  public:
  59   class CONTENT_EXPORT Comparator : public LevelDBComparator {
  60    public:
  61     int Compare(const base::StringPiece& a,
  62                 const base::StringPiece& b) const override;
  63     const char* Name() const override;
  64   };
  65
  66   class CONTENT_EXPORT RecordIdentifier {
  67    public:
  68     RecordIdentifier(const std::string& primary_key, int64 version);
  69     RecordIdentifier();
  70     ~RecordIdentifier();
  71
  72     const std::string& primary_key() const { return primary_key_; }
  73     int64 version() const { return version_; }
  74     void Reset(const std::string& primary_key, int64 version) {
  75       primary_key_ = primary_key;
  76       version_ = version;
  77     }
  78
  79    private:
  80     // TODO(jsbell): Make it more clear that this is the *encoded* version of
  81     // the key.
  82     std::string primary_key_;
  83     int64 version_;
  84     DISALLOW_COPY_AND_ASSIGN(RecordIdentifier);
  85   };
  86
  87   class BlobWriteCallback : public base::RefCounted<BlobWriteCallback> {
  88    public:
  89     virtual void Run(bool succeeded) = 0;
  90
  91    protected:
  92     friend class base::RefCounted<BlobWriteCallback>;
  93     virtual ~BlobWriteCallback() {}
  94   };
  95
  96   class BlobChangeRecord {
  97    public:
  98     BlobChangeRecord(const std::string& key, int64 object_store_id);
  99     ~BlobChangeRecord();
 100
 101     const std::string& key() const { return key_; }
 102     int64 object_store_id() const { return object_store_id_; }
 103     void SetBlobInfo(std::vector<IndexedDBBlobInfo>* blob_info);
 104     std::vector<IndexedDBBlobInfo>& mutable_blob_info() { return blob_info_; }
 105     const std::vector<IndexedDBBlobInfo>& blob_info() const {
 106       return blob_info_;
 107     }
 108     void SetHandles(ScopedVector<storage::BlobDataHandle>* handles);
 109     scoped_ptr<BlobChangeRecord> Clone() const;
 110
 111    private:
 112     std::string key_;
 113     int64 object_store_id_;
 114     std::vector<IndexedDBBlobInfo> blob_info_;
 115     ScopedVector<storage::BlobDataHandle> handles_;
 116     DISALLOW_COPY_AND_ASSIGN(BlobChangeRecord);
 117   };
 118   typedef std::map<std::string, BlobChangeRecord*> BlobChangeMap;
 119
 120   class CONTENT_EXPORT Transaction {
 121    public:
 122     explicit Transaction(IndexedDBBackingStore* backing_store);
 123     virtual ~Transaction();
 124
 125     virtual void Begin();
 126     // The callback will be called eventually on success or failure, or
 127     // immediately if phase one is complete due to lack of any blobs to write.
 128     virtual leveldb::Status CommitPhaseOne(scoped_refptr<BlobWriteCallback>);
 129     virtual leveldb::Status CommitPhaseTwo();
 130     virtual void Rollback();
 131     void Reset() {
 132       backing_store_ = NULL;
 133       transaction_ = NULL;
 134     }
 135     leveldb::Status PutBlobInfoIfNeeded(
 136         int64 database_id,
 137         int64 object_store_id,
 138         const std::string& object_store_data_key,
 139         std::vector<IndexedDBBlobInfo>*,
 140         ScopedVector<storage::BlobDataHandle>* handles);
 141     void PutBlobInfo(int64 database_id,
 142                      int64 object_store_id,
 143                      const std::string& object_store_data_key,
 144                      std::vector<IndexedDBBlobInfo>*,
 145                      ScopedVector<storage::BlobDataHandle>* handles);
 146
 147     LevelDBTransaction* transaction() { return transaction_.get(); }
 148
 149     leveldb::Status GetBlobInfoForRecord(
 150         int64 database_id,
 151         const std::string& object_store_data_key,
 152         IndexedDBValue* value);
 153
 154     // This holds a BlobEntryKey and the encoded IndexedDBBlobInfo vector stored
 155     // under that key.
 156     typedef std::vector<std::pair<BlobEntryKey, std::string> >
 157         BlobEntryKeyValuePairVec;
 158
 159     class WriteDescriptor {
 160      public:
 161       WriteDescriptor(const GURL& url, int64_t key, int64_t size);
 162       WriteDescriptor(const base::FilePath& path,
 163                       int64_t key,
 164                       int64_t size,
 165                       base::Time last_modified);
 166
 167       bool is_file() const { return is_file_; }
 168       const GURL& url() const {
 169         DCHECK(!is_file_);
 170         return url_;
 171       }
 172       const base::FilePath& file_path() const {
 173         DCHECK(is_file_);
 174         return file_path_;
 175       }
 176       int64_t key() const { return key_; }
 177       int64_t size() const { return size_; }
 178       base::Time last_modified() const { return last_modified_; }
 179
 180      private:
 181       bool is_file_;
 182       GURL url_;
 183       base::FilePath file_path_;
 184       int64_t key_;
 185       int64_t size_;
 186       base::Time last_modified_;
 187     };
 188
 189     class ChainedBlobWriter
 190         : public base::RefCountedThreadSafe<ChainedBlobWriter> {
 191      public:
 192       virtual void set_delegate(
 193           scoped_ptr<storage::FileWriterDelegate> delegate) = 0;
 194
 195       // TODO(ericu): Add a reason in the event of failure.
 196       virtual void ReportWriteCompletion(bool succeeded,
 197                                          int64 bytes_written) = 0;
 198
 199       virtual void Abort() = 0;
 200
 201      protected:
 202       friend class base::RefCountedThreadSafe<ChainedBlobWriter>;
 203       virtual ~ChainedBlobWriter() {}
 204     };
 205
 206     class ChainedBlobWriterImpl;
 207
 208     typedef std::vector<WriteDescriptor> WriteDescriptorVec;
 209
 210    private:
 211     class BlobWriteCallbackWrapper;
 212
 213     leveldb::Status HandleBlobPreTransaction(
 214         BlobEntryKeyValuePairVec* new_blob_entries,
 215         WriteDescriptorVec* new_files_to_write);
 216     // Returns true on success, false on failure.
 217     bool CollectBlobFilesToRemove();
 218     // The callback will be called eventually on success or failure.
 219     void WriteNewBlobs(BlobEntryKeyValuePairVec* new_blob_entries,
 220                        WriteDescriptorVec* new_files_to_write,
 221                        scoped_refptr<BlobWriteCallback> callback);
 222     leveldb::Status SortBlobsToRemove();
 223
 224     IndexedDBBackingStore* backing_store_;
 225     scoped_refptr<LevelDBTransaction> transaction_;
 226     BlobChangeMap blob_change_map_;
 227     BlobChangeMap incognito_blob_map_;
 228     int64 database_id_;
 229     BlobJournalType blobs_to_remove_;
 230     scoped_refptr<ChainedBlobWriter> chained_blob_writer_;
 231   };
 232
 233   class Cursor {
 234    public:
 235     enum IteratorState { READY = 0, SEEK };
 236
 237     virtual ~Cursor();
 238
 239     struct CursorOptions {
 240       CursorOptions();
 241       ~CursorOptions();
 242       int64 database_id;
 243       int64 object_store_id;
 244       int64 index_id;
 245       std::string low_key;
 246       bool low_open;
 247       std::string high_key;
 248       bool high_open;
 249       bool forward;
 250       bool unique;
 251     };
 252
 253     const IndexedDBKey& key() const { return *current_key_; }
 254     bool Continue(leveldb::Status* s) { return Continue(NULL, NULL, SEEK, s); }
 255     bool Continue(const IndexedDBKey* key,
 256                   IteratorState state,
 257                   leveldb::Status* s) {
 258       return Continue(key, NULL, state, s);
 259     }
 260     bool Continue(const IndexedDBKey* key,
 261                   const IndexedDBKey* primary_key,
 262                   IteratorState state,
 263                   leveldb::Status*);
 264     bool Advance(uint32 count, leveldb::Status*);
 265     bool FirstSeek(leveldb::Status*);
 266
 267     virtual Cursor* Clone() = 0;
 268     virtual const IndexedDBKey& primary_key() const;
 269     virtual IndexedDBValue* value() = 0;
 270     virtual const RecordIdentifier& record_identifier() const;
 271     virtual bool LoadCurrentRow() = 0;
 272
 273    protected:
 274     Cursor(scoped_refptr<IndexedDBBackingStore> backing_store,
 275            Transaction* transaction,
 276            int64 database_id,
 277            const CursorOptions& cursor_options);
 278     explicit Cursor(const IndexedDBBackingStore::Cursor* other);
 279
 280     virtual std::string EncodeKey(const IndexedDBKey& key) = 0;
 281     virtual std::string EncodeKey(const IndexedDBKey& key,
 282                                   const IndexedDBKey& primary_key) = 0;
 283
 284     bool IsPastBounds() const;
 285     bool HaveEnteredRange() const;
 286
 287     IndexedDBBackingStore* backing_store_;
 288     Transaction* transaction_;
 289     int64 database_id_;
 290     const CursorOptions cursor_options_;
 291     scoped_ptr<LevelDBIterator> iterator_;
 292     scoped_ptr<IndexedDBKey> current_key_;
 293     IndexedDBBackingStore::RecordIdentifier record_identifier_;
 294
 295    private:
 296     DISALLOW_COPY_AND_ASSIGN(Cursor);
 297   };
 298
 299   const GURL& origin_url() const { return origin_url_; }
 300   IndexedDBFactory* factory() const { return indexed_db_factory_; }
 301   base::SequencedTaskRunner* task_runner() const { return task_runner_.get(); }
 302   base::OneShotTimer<IndexedDBBackingStore>* close_timer() {
 303     return &close_timer_;
 304   }
 305   IndexedDBActiveBlobRegistry* active_blob_registry() {
 306     return &active_blob_registry_;
 307   }
 308
 309   static scoped_refptr<IndexedDBBackingStore> Open(
 310       IndexedDBFactory* indexed_db_factory,
 311       const GURL& origin_url,
 312       const base::FilePath& path_base,
 313       net::URLRequestContext* request_context,
 314       blink::WebIDBDataLoss* data_loss,
 315       std::string* data_loss_message,
 316       bool* disk_full,
 317       base::SequencedTaskRunner* task_runner,
 318       bool clean_journal,
 319       leveldb::Status* status);
 320   static scoped_refptr<IndexedDBBackingStore> Open(
 321       IndexedDBFactory* indexed_db_factory,
 322       const GURL& origin_url,
 323       const base::FilePath& path_base,
 324       net::URLRequestContext* request_context,
 325       blink::WebIDBDataLoss* data_loss,
 326       std::string* data_loss_message,
 327       bool* disk_full,
 328       LevelDBFactory* leveldb_factory,
 329       base::SequencedTaskRunner* task_runner,
 330       bool clean_journal,
 331       leveldb::Status* status);
 332   static scoped_refptr<IndexedDBBackingStore> OpenInMemory(
 333       const GURL& origin_url,
 334       base::SequencedTaskRunner* task_runner,
 335       leveldb::Status* status);
 336   static scoped_refptr<IndexedDBBackingStore> OpenInMemory(
 337       const GURL& origin_url,
 338       LevelDBFactory* leveldb_factory,
 339       base::SequencedTaskRunner* task_runner,
 340       leveldb::Status* status);
 341
 342   void GrantChildProcessPermissions(int child_process_id);
 343
 344   // Compact is public for testing.
 345   virtual void Compact();
 346   virtual std::vector<base::string16> GetDatabaseNames(leveldb::Status*);
 347   virtual leveldb::Status GetIDBDatabaseMetaData(
 348       const base::string16& name,
 349       IndexedDBDatabaseMetadata* metadata,
 350       bool* success) WARN_UNUSED_RESULT;
 351   virtual leveldb::Status CreateIDBDatabaseMetaData(
 352       const base::string16& name,
 353       const base::string16& version,
 354       int64 int_version,
 355       int64* row_id);
 356   virtual bool UpdateIDBDatabaseIntVersion(
 357       IndexedDBBackingStore::Transaction* transaction,
 358       int64 row_id,
 359       int64 int_version);
 360   virtual leveldb::Status DeleteDatabase(const base::string16& name);
 361
 362   // Assumes caller has already closed the backing store.
 363   static leveldb::Status DestroyBackingStore(const base::FilePath& path_base,
 364                                              const GURL& origin_url);
 365   static bool RecordCorruptionInfo(const base::FilePath& path_base,
 366                                    const GURL& origin_url,
 367                                    const std::string& message);
 368   leveldb::Status GetObjectStores(
 369       int64 database_id,
 370       IndexedDBDatabaseMetadata::ObjectStoreMap* map) WARN_UNUSED_RESULT;
 371   virtual leveldb::Status CreateObjectStore(
 372       IndexedDBBackingStore::Transaction* transaction,
 373       int64 database_id,
 374       int64 object_store_id,
 375       const base::string16& name,
 376       const IndexedDBKeyPath& key_path,
 377       bool auto_increment);
 378   virtual leveldb::Status DeleteObjectStore(
 379       IndexedDBBackingStore::Transaction* transaction,
 380       int64 database_id,
 381       int64 object_store_id) WARN_UNUSED_RESULT;
 382
 383   virtual leveldb::Status GetRecord(
 384       IndexedDBBackingStore::Transaction* transaction,
 385       int64 database_id,
 386       int64 object_store_id,
 387       const IndexedDBKey& key,
 388       IndexedDBValue* record) WARN_UNUSED_RESULT;
 389   virtual leveldb::Status PutRecord(
 390       IndexedDBBackingStore::Transaction* transaction,
 391       int64 database_id,
 392       int64 object_store_id,
 393       const IndexedDBKey& key,
 394       IndexedDBValue* value,
 395       ScopedVector<storage::BlobDataHandle>* handles,
 396       RecordIdentifier* record) WARN_UNUSED_RESULT;
 397   virtual leveldb::Status ClearObjectStore(
 398       IndexedDBBackingStore::Transaction* transaction,
 399       int64 database_id,
 400       int64 object_store_id) WARN_UNUSED_RESULT;
 401   virtual leveldb::Status DeleteRecord(
 402       IndexedDBBackingStore::Transaction* transaction,
 403       int64 database_id,
 404       int64 object_store_id,
 405       const RecordIdentifier& record) WARN_UNUSED_RESULT;
 406   virtual leveldb::Status DeleteRange(
 407       IndexedDBBackingStore::Transaction* transaction,
 408       int64 database_id,
 409       int64 object_store_id,
 410       const IndexedDBKeyRange&) WARN_UNUSED_RESULT;
 411   virtual leveldb::Status GetKeyGeneratorCurrentNumber(
 412       IndexedDBBackingStore::Transaction* transaction,
 413       int64 database_id,
 414       int64 object_store_id,
 415       int64* current_number) WARN_UNUSED_RESULT;
 416   virtual leveldb::Status MaybeUpdateKeyGeneratorCurrentNumber(
 417       IndexedDBBackingStore::Transaction* transaction,
 418       int64 database_id,
 419       int64 object_store_id,
 420       int64 new_state,
 421       bool check_current) WARN_UNUSED_RESULT;
 422   virtual leveldb::Status KeyExistsInObjectStore(
 423       IndexedDBBackingStore::Transaction* transaction,
 424       int64 database_id,
 425       int64 object_store_id,
 426       const IndexedDBKey& key,
 427       RecordIdentifier* found_record_identifier,
 428       bool* found) WARN_UNUSED_RESULT;
 429
 430   virtual leveldb::Status CreateIndex(
 431       IndexedDBBackingStore::Transaction* transaction,
 432       int64 database_id,
 433       int64 object_store_id,
 434       int64 index_id,
 435       const base::string16& name,
 436       const IndexedDBKeyPath& key_path,
 437       bool is_unique,
 438       bool is_multi_entry) WARN_UNUSED_RESULT;
 439   virtual leveldb::Status DeleteIndex(
 440       IndexedDBBackingStore::Transaction* transaction,
 441       int64 database_id,
 442       int64 object_store_id,
 443       int64 index_id) WARN_UNUSED_RESULT;
 444   virtual leveldb::Status PutIndexDataForRecord(
 445       IndexedDBBackingStore::Transaction* transaction,
 446       int64 database_id,
 447       int64 object_store_id,
 448       int64 index_id,
 449       const IndexedDBKey& key,
 450       const RecordIdentifier& record) WARN_UNUSED_RESULT;
 451   virtual leveldb::Status GetPrimaryKeyViaIndex(
 452       IndexedDBBackingStore::Transaction* transaction,
 453       int64 database_id,
 454       int64 object_store_id,
 455       int64 index_id,
 456       const IndexedDBKey& key,
 457       scoped_ptr<IndexedDBKey>* primary_key) WARN_UNUSED_RESULT;
 458   virtual leveldb::Status KeyExistsInIndex(
 459       IndexedDBBackingStore::Transaction* transaction,
 460       int64 database_id,
 461       int64 object_store_id,
 462       int64 index_id,
 463       const IndexedDBKey& key,
 464       scoped_ptr<IndexedDBKey>* found_primary_key,
 465       bool* exists) WARN_UNUSED_RESULT;
 466
 467   // Public for IndexedDBActiveBlobRegistry::ReleaseBlobRef.
 468   virtual void ReportBlobUnused(int64 database_id, int64 blob_key);
 469
 470   base::FilePath GetBlobFileName(int64 database_id, int64 key);
 471
 472   virtual scoped_ptr<Cursor> OpenObjectStoreKeyCursor(
 473       IndexedDBBackingStore::Transaction* transaction,
 474       int64 database_id,
 475       int64 object_store_id,
 476       const IndexedDBKeyRange& key_range,
 477       blink::WebIDBCursorDirection,
 478       leveldb::Status*);
 479   virtual scoped_ptr<Cursor> OpenObjectStoreCursor(
 480       IndexedDBBackingStore::Transaction* transaction,
 481       int64 database_id,
 482       int64 object_store_id,
 483       const IndexedDBKeyRange& key_range,
 484       blink::WebIDBCursorDirection,
 485       leveldb::Status*);
 486   virtual scoped_ptr<Cursor> OpenIndexKeyCursor(
 487       IndexedDBBackingStore::Transaction* transaction,
 488       int64 database_id,
 489       int64 object_store_id,
 490       int64 index_id,
 491       const IndexedDBKeyRange& key_range,
 492       blink::WebIDBCursorDirection,
 493       leveldb::Status*);
 494   virtual scoped_ptr<Cursor> OpenIndexCursor(
 495       IndexedDBBackingStore::Transaction* transaction,
 496       int64 database_id,
 497       int64 object_store_id,
 498       int64 index_id,
 499       const IndexedDBKeyRange& key_range,
 500       blink::WebIDBCursorDirection,
 501       leveldb::Status*);
 502
 503  protected:
 504   friend class base::RefCounted<IndexedDBBackingStore>;
 505
 506   IndexedDBBackingStore(IndexedDBFactory* indexed_db_factory,
 507                         const GURL& origin_url,
 508                         const base::FilePath& blob_path,
 509                         net::URLRequestContext* request_context,
 510                         scoped_ptr<LevelDBDatabase> db,
 511                         scoped_ptr<LevelDBComparator> comparator,
 512                         base::SequencedTaskRunner* task_runner);
 513   virtual ~IndexedDBBackingStore();
 514
 515   bool is_incognito() const { return !indexed_db_factory_; }
 516
 517   leveldb::Status SetUpMetadata();
 518
 519   virtual bool WriteBlobFile(
 520       int64 database_id,
 521       const Transaction::WriteDescriptor& descriptor,
 522       Transaction::ChainedBlobWriter* chained_blob_writer);
 523   virtual bool RemoveBlobFile(int64 database_id, int64 key);
 524   virtual void StartJournalCleaningTimer();
 525   void CleanPrimaryJournalIgnoreReturn();
 526
 527  private:
 528   static scoped_refptr<IndexedDBBackingStore> Create(
 529       IndexedDBFactory* indexed_db_factory,
 530       const GURL& origin_url,
 531       const base::FilePath& blob_path,
 532       net::URLRequestContext* request_context,
 533       scoped_ptr<LevelDBDatabase> db,
 534       scoped_ptr<LevelDBComparator> comparator,
 535       base::SequencedTaskRunner* task_runner,
 536       leveldb::Status* status);
 537
 538   static bool ReadCorruptionInfo(const base::FilePath& path_base,
 539                                  const GURL& origin_url,
 540                                  std::string* message);
 541
 542   leveldb::Status FindKeyInIndex(
 543       IndexedDBBackingStore::Transaction* transaction,
 544       int64 database_id,
 545       int64 object_store_id,
 546       int64 index_id,
 547       const IndexedDBKey& key,
 548       std::string* found_encoded_primary_key,
 549       bool* found);
 550   leveldb::Status GetIndexes(int64 database_id,
 551                              int64 object_store_id,
 552                              IndexedDBObjectStoreMetadata::IndexMap* map)
 553       WARN_UNUSED_RESULT;
 554   bool RemoveBlobDirectory(int64 database_id);
 555   leveldb::Status CleanUpBlobJournal(const std::string& level_db_key);
 556
 557   IndexedDBFactory* indexed_db_factory_;
 558   const GURL origin_url_;
 559   base::FilePath blob_path_;
 560
 561   // The origin identifier is a key prefix unique to the origin used in the
 562   // leveldb backing store to partition data by origin. It is a normalized
 563   // version of the origin URL with a versioning suffix appended, e.g.
 564   // "http_localhost_81@1" Since only one origin is stored per backing store
 565   // this is redundant but necessary for backwards compatibility; the suffix
 566   // provides for future flexibility.
 567   const std::string origin_identifier_;
 568
 569   net::URLRequestContext* request_context_;
 570   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 571   std::set<int> child_process_ids_granted_;
 572   BlobChangeMap incognito_blob_map_;
 573   base::OneShotTimer<IndexedDBBackingStore> journal_cleaning_timer_;
 574
 575   scoped_ptr<LevelDBDatabase> db_;
 576   scoped_ptr<LevelDBComparator> comparator_;
 577   // Whenever blobs are registered in active_blob_registry_, indexed_db_factory_
 578   // will hold a reference to this backing store.
 579   IndexedDBActiveBlobRegistry active_blob_registry_;
 580   base::OneShotTimer<IndexedDBBackingStore> close_timer_;
 581
 582   DISALLOW_COPY_AND_ASSIGN(IndexedDBBackingStore);
 583 };
 584
 585 }  // namespace content
 586
 587 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_BACKING_STORE_H_