webrtc-pc

96338fee - Making getParameters/setParameters matching logic more deterministic.

Making getParameters/setParameters matching logic more deterministic. Partially fixes #1488, though there are still remaining issues (#1520). Introduces a "[[LastReturnedParameters]]" internal slot to specify how InvalidModificationErrors are returned, rather than invoking the `getParameters()` algorithm directly (which doesn't make sense if interpreting the spec literally, since this would always result in a new `transactionId` and an InvalidModificationError).