Bug 1507229 - Argument sanity check at CreateMutableFile() to avoid assertion failure r=janv

CreateMutableFile() doesn't allow empty name, we should check it before
further processing to avoid assertion failure.

Differential Revision: https://phabricator.services.mozilla.com/D23999

--HG--
extra : moz-landing-system : lando

dom/indexedDB/IDBDatabase.cpp

@@ -667,6 +667,11 @@ already_AddRefed<IDBRequest> IDBDatabase::CreateMutableFile(
     ErrorResult& aRv) {
   AssertIsOnOwningThread();
 
+  if (aName.IsEmpty()) {
+    aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
+    return nullptr;
+  }
+
   if (QuotaManager::IsShuttingDown()) {
     IDB_REPORT_INTERNAL_ERR();
     aRv.Throw(NS_ERROR_DOM_INDEXEDDB_UNKNOWN_ERR);

dom/indexedDB/crashtests/1507229-1.html

@@ -0,0 +1,5 @@
+<script>
+  window.indexedDB.open("hello").onsuccess = function(event) {
+    event.target.result.createMutableFile("");
+  }
+</script>

dom/indexedDB/crashtests/crashtests.list

@@ -1 +1,2 @@
 load 726376-1.html
+load 1507229-1.html