Prevent a Deferred from firing twice when an IndexedDB version change…

… is blocked.

R=nweiz
DELTA=10  (8 added, 0 deleted, 2 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=5769


git-svn-id: http://closure-library.googlecode.com/svn/trunk@2271 0b95b8e8-c90f-11de-9d4f-f947ee5921c8

closure/goog/db/indexeddb.js

@@ -165,10 +165,18 @@ goog.db.IndexedDb.prototype.setVersion = function(version) {
     d.callback(new goog.db.Transaction(ev.target.result));
   };
   request.onerror = function(ev) {
-    d.errback(new goog.db.Error(ev.target.errorCode, 'setting version'));
+    // If a version change is blocked, onerror and onblocked may both fire.
+    // Check d.hasFired() to avoid an AlreadyCalledError.
+    if (!d.hasFired()) {
+      d.errback(new goog.db.Error(ev.target.errorCode, 'setting version'));
+    }
   };
   request.onblocked = function(ev) {
-    d.errback(new goog.db.Error.VersionChangeBlockedError());
+    // If a version change is blocked, onerror and onblocked may both fire.
+    // Check d.hasFired() to avoid an AlreadyCalledError.
+    if (!d.hasFired()) {
+      d.errback(new goog.db.Error.VersionChangeBlockedError());
+    }
   };
   return d;
 };