The percentage of volume space that can be used for data storage for every domain. If the maximum storage is reached the storage request will fail with a QuotaExceededError exception. A value of 0.0 means that data storage is not allowed. A value of -1.0, which is the default, means WebKit will use the default quota (1 GiB).
Builder instance for fluent chaining
Set originStorageRatio property.