Add most of the metadata-handling code for blobs. It's not quite all there, but

this is the biggest chunk I can pull out vaguely cleanly.  It does contain a
couple of fake calls to keep the compiler happy.
This CL also makes SetUpMetadata a member in order to ease testing in a later CL.

This depends on https://codereview.chromium.org/261843004/.

BUG=108012

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270016

Review URL: https://codereview.chromium.org/266333002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@273048 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/indexed_db/indexed_db_backing_store.h

@@ -308,7 +308,9 @@ class CONTENT_EXPORT IndexedDBBackingStore
     virtual bool LoadCurrentRow() = 0;
 
    protected:
-    Cursor(LevelDBTransaction* transaction,
+    Cursor(scoped_refptr<IndexedDBBackingStore> backing_store,
+           Transaction* transaction,
+           int64 database_id,
            const CursorOptions& cursor_options);
     explicit Cursor(const IndexedDBBackingStore::Cursor* other);
 
@@ -319,7 +321,9 @@ class CONTENT_EXPORT IndexedDBBackingStore
     bool IsPastBounds() const;
     bool HaveEnteredRange() const;
 
-    LevelDBTransaction* transaction_;
+    IndexedDBBackingStore* backing_store_;
+    Transaction* transaction_;
+    int64 database_id_;
     const CursorOptions cursor_options_;
     scoped_ptr<LevelDBIterator> iterator_;
     scoped_ptr<IndexedDBKey> current_key_;
@@ -399,6 +403,11 @@ class CONTENT_EXPORT IndexedDBBackingStore
 
     LevelDBTransaction* transaction() { return transaction_; }
 
+    leveldb::Status GetBlobInfoForRecord(
+        int64 database_id,
+        const std::string& object_store_data_key,
+        IndexedDBValue* value);
+
     // This holds a BlobEntryKey and the encoded IndexedDBBlobInfo vector stored
     // under that key.
     typedef std::vector<std::pair<BlobEntryKey, std::string> >
@@ -475,6 +484,8 @@ class CONTENT_EXPORT IndexedDBBackingStore
 
   bool is_incognito() const { return !indexed_db_factory_; }
 
+  bool SetUpMetadata();
+
   virtual bool WriteBlobFile(
       int64 database_id,
       const Transaction::WriteDescriptor& descriptor,

content/browser/indexed_db/indexed_db_leveldb_coding.cc

@@ -46,7 +46,8 @@
 // <0, 0, 0, 2> => SerializedScriptValue version [DataVersionKey]
 // <0, 0, 0, 3>
 //   => Blob journal
-//     The format of the journal is: {database_id, blobKey}*.
+//     The format of the journal is:
+//         {database_id (var int), blobKey (var int)}*.
 //     If the blobKey is kAllBlobsKey, the whole database should be deleted.
 //     [BlobJournalKey]
 // <0, 0, 0, 4> => Live blob journal; same format. [LiveBlobJournalKey]