Quota: Add null check

Source/modules/quota/StorageQuota.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 88 matching lines @@
     KURL storagePartition = KURL(KURL(), securityOrigin->toString());
     OwnPtr<StorageQuotaCallbacks> callbacks = StorageQuotaCallbacksImpl::create(resolver, executionContext);
     blink::Platform::current()->queryStorageUsageAndQuota(storagePartition, stringToStorageQuotaType(type), callbacks.release());
     return promise;
 }
 
 ScriptPromise StorageQuota::requestPersistentQuota(ExecutionContext* executionContext, unsigned long long newQuota)
 {
     ASSERT(executionContext);
 
-    return StorageQuotaClient::from(executionContext)->requestPersistentQuota(executionContext, newQuota);
+    StorageQuotaClient* client = StorageQuotaClient::from(executionContext);
+    if (!client) {
+        RefPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(executionContext);
+        resolver->reject(DOMError::create(NotSupportedError));
+        return resolver->promise();
+    }
+
+    return client->requestPersistentQuota(executionContext, newQuota);
 }
 
 StorageQuota::~StorageQuota()
 {
 }
 
 } // namespace WebCore