Speed up IDB by trimming down the BlobChangeMaps. Check to see if we need each

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 <set>
 #include <string>
 #include <vector>
@@ skipping 389 matching lines @@
     virtual void Begin();
     // The callback will be called eventually on success or failure, or
     // immediately if phase one is complete due to lack of any blobs to write.
     virtual leveldb::Status CommitPhaseOne(scoped_refptr<BlobWriteCallback>);
     virtual leveldb::Status CommitPhaseTwo();
     virtual void Rollback();
     void Reset() {
       backing_store_ = NULL;
       transaction_ = NULL;
     }
+    leveldb::Status PutBlobInfoIfNeeded(
+        int64 database_id,
+        int64 object_store_id,
+        const std::string& object_store_data_key,
+        std::vector<IndexedDBBlobInfo>*,
+        ScopedVector<webkit_blob::BlobDataHandle>* handles);
     void PutBlobInfo(int64 database_id,
                      int64 object_store_id,
                      const std::string& object_store_data_key,
                      std::vector<IndexedDBBlobInfo>*,
                      ScopedVector<webkit_blob::BlobDataHandle>* handles);
 
     LevelDBTransaction* transaction() { return transaction_; }
 
     leveldb::Status GetBlobInfoForRecord(
         int64 database_id,
@@ skipping 147 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_