Revert of Revert of Reland: Optimizes IndexedDB's DeleteDatabase when no db exists

content/browser/indexed_db/indexed_db_browsertest.cc

Index: content/browser/indexed_db/indexed_db_browsertest.cc
diff --git a/content/browser/indexed_db/indexed_db_browsertest.cc b/content/browser/indexed_db/indexed_db_browsertest.cc
index cf5b049e059673225cab5f9eb8b0ba0dae044f9a..5b78ac56896c3c354d7e93f434a9df94aca30204 100644
--- a/content/browser/indexed_db/indexed_db_browsertest.cc
+++ b/content/browser/indexed_db/indexed_db_browsertest.cc
@@ -487,22 +487,14 @@
   //       => IndexedDBBackingStore::SetUpMetadata
   //   #2: IndexedDBBackingStore::OpenBackingStore
   //       => IndexedDBBackingStore::CleanUpBlobJournal (no-op)
-  // * Then deletes the database:
-  //   #3: IndexedDBFactoryImpl::DeleteDatabase
+  // * The test calls open(), to create a new database:
+  //   #3: IndexedDBFactoryImpl::Open
   //       => IndexedDBDatabase::Create
   //       => IndexedDBBackingStore::CreateIDBDatabaseMetaData
-  //   #4: IndexedDBFactoryImpl::DeleteDatabase
-  //       => IndexedDBDatabase::DeleteDatabase
-  //       => IndexedDBBackingStore::DeleteDatabase
-  //       => IndexedDBBackingStore::CleanUpBlobJournal (no-op)
-  // * The test calls open(), to create a new database:
-  //   #5: IndexedDBFactoryImpl::Open
-  //       => IndexedDBDatabase::Create
-  //       => IndexedDBBackingStore::CreateIDBDatabaseMetaData
-  //   #6: IndexedDBTransaction::Commit - initial "versionchange" transaction
+  //   #4: IndexedDBTransaction::Commit - initial "versionchange" transaction
   // * Once the connection is opened, the test runs:
-  //   #7: IndexedDBTransaction::Commit - the test's "readwrite" transaction)
-  const int instance_num = 7;
+  //   #5: IndexedDBTransaction::Commit - the test's "readwrite" transaction)
+  const int instance_num = 5;
   const int call_num = 1;
   FailOperation(FAIL_CLASS_LEVELDB_TRANSACTION, FAIL_METHOD_COMMIT_DISK_FULL,
                 instance_num, call_num);