Roll libjingle's chromium_revision 176094:176396

Picks up an update to libvpx.gyp to ease targeting Android.

Review URL: https://webrtc-codereview.appspot.com/1124004

git-svn-id: http://libjingle.googlecode.com/svn/trunk@285 dd674b97-3498-5ee5-1854-bdd07cd0ff33