[IndexedDB] Refactoring to remove ref ptrs and host transaction ids.

content/browser/indexed_db/mock_indexed_db_database_callbacks.cc

Index: content/browser/indexed_db/mock_indexed_db_database_callbacks.cc
diff --git a/content/browser/indexed_db/mock_indexed_db_database_callbacks.cc b/content/browser/indexed_db/mock_indexed_db_database_callbacks.cc
index 1125bdecb3b0d9ff6f19811d66c5c543d18b6790..9cd07ff9061d4d0c37eae3dad91766dc4eb1d7b1 100644
--- a/content/browser/indexed_db/mock_indexed_db_database_callbacks.cc
+++ b/content/browser/indexed_db/mock_indexed_db_database_callbacks.cc
@@ -18,7 +18,7 @@ void MockIndexedDBDatabaseCallbacks::OnForcedClose() {
 }
 

[cmumford, 2016/11/04 23:33:13]

If I'm correct, the only time this is called is as so:

 OnAbort(*this, ...)

Why not just make this accept a pointer?

[dmurph, 2016/11/07 20:05:23]

There's no reason that the callbacks need to modify the transaction. I'm
defaulting to the most constrained method declaration that we need to prevent
unwanted use. const ref unless we explicitly need modification.

 void MockIndexedDBDatabaseCallbacks::OnAbort(
-    int64_t transaction_id,
+    const IndexedDBTransaction& transaction,
     const IndexedDBDatabaseError& error) {
   abort_called_ = true;
 }