[IndexedDB] Adding transaction and value support to observers

content/browser/indexed_db/indexed_db_connection.cc

Index: content/browser/indexed_db/indexed_db_connection.cc
diff --git a/content/browser/indexed_db/indexed_db_connection.cc b/content/browser/indexed_db/indexed_db_connection.cc
index 216786a1d365f783f207895b0158fbce7808eab7..5f98d84c6fa3270a28c2a1e1df34a3b4342432bc 100644
--- a/content/browser/indexed_db/indexed_db_connection.cc
+++ b/content/browser/indexed_db/indexed_db_connection.cc
@@ -158,4 +158,12 @@ void IndexedDBConnection::RemoveTransaction(int64_t id) {
   transactions_.erase(id);
 }
 
+int64_t IndexedDBConnection::NextObserverTransactionId() {

[cmumford, 2017/01/09 21:31:25]

nit: "Next*" might be interpreted as a read-only operation. What do you think
about AllocObserverTransactionId()?

[dmurph, 2017/01/10 00:17:38]

NewObserverTransactionId?

+  // If we ever overflow, just reset the ID.
+  if (next_observer_transaction_id_ == kMaxObserverTransactionId) {
+    next_observer_transaction_id_ = 1ll << 32;
+  }
+  return next_observer_transaction_id_++;
+}
+
 }  // namespace content