Replace disabled logging with a restricted logging mode.

This will enable some low-level webrtc logging in a Chromium build,
while limiting the binary size impact.

For a Mac Release build, it results in an increase to Chrome.app of 37k
and libpeerconnection.so of 25k. For comparison, enabling full logs
costs 230k and 218k respectively.

BUG=b/11470432
TESTED=voe_cmd_test produces logs of the appropriate severity.
R=fischman@webrtc.org, henrikg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/3479004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@5097 4adac7df-926f-26a2-2b94-8c16560cd09d
7 files changed