Current implementation of JavaToStdString applies additional encoding that modifies ISO-8859-1 encoded strings (e.g. byte array). This CL is to fix this.
A planned use of this is to pass a protobuf serialized string as a MediaConstraint to WebRTC to configure audio network adaptor.
BUG=webrtc:6815
Review-Url: https://codereview.webrtc.org/2549783002
Cr-Commit-Position: refs/heads/master@{#15509}