--- a/dom/storage/DOMStorageManager.cpp
+++ b/dom/storage/DOMStorageManager.cpp
@@ -509,17 +509,20 @@ DOMStorageManager::ClearCaches(uint32_t 
 }
 
 nsresult
 DOMStorageManager::Observe(const char* aTopic,
                            const nsAString& aOriginAttributesPattern,
                            const nsACString& aOriginScope)
 {
   OriginAttributesPattern pattern;
-  pattern.Init(aOriginAttributesPattern);
+  if (!pattern.Init(aOriginAttributesPattern)) {
+    NS_ERROR("Cannot parse origin attributes pattern");
+    return NS_ERROR_FAILURE;
+  }
 
   // Clear everything, caches + database
   if (!strcmp(aTopic, "cookie-cleared")) {
     ClearCaches(DOMStorageCache::kUnloadComplete, pattern, EmptyCString());
     return NS_OK;
   }
 
   // Clear from caches everything that has been stored