IDB: Make readonly transactions wait for earlier readwrite transactions

content/browser/indexed_db/indexed_db_transaction_coordinator.cc

Index: content/browser/indexed_db/indexed_db_transaction_coordinator.cc
diff --git a/content/browser/indexed_db/indexed_db_transaction_coordinator.cc b/content/browser/indexed_db/indexed_db_transaction_coordinator.cc
index ca7f3838b880009e7d020070847285b89ad3b362..c00c5fb466fd508fcaa09747b4b4b6fcc102e8bc 100644
--- a/content/browser/indexed_db/indexed_db_transaction_coordinator.cc
+++ b/content/browser/indexed_db/indexed_db_transaction_coordinator.cc
@@ -146,8 +146,6 @@ bool IndexedDBTransactionCoordinator::CanStartTransaction(
       return true;
 
     case blink::WebIDBTransactionModeReadOnly:
-      return true;
-
     case blink::WebIDBTransactionModeReadWrite:
       return !DoSetsIntersect(transaction->scope(), locked_scope);
   }