PeerConnection(java): replace ScopedLocalRef with ScopedLocalRefFrame and fix a local reference leak in OnMessage.
PeerConnection(java): replace ScopedLocalRef with ScopedLocalRefFrame and fix a local reference leak in OnMessage.

Hopefully the approach of pushing/popping frames will be easier to avoid messing up than remembering to annotate every single local reference with a ScopedLocalRef.

BUG=2761
R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/6729004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 4177615e87e1a92ffdf403c4ef1b09437ae4f43a

sippet/talk,sippet/talk,sippet/talk,sippet/talk,sippet/talk