Chromium defines ENABLE_PROFILING under the gyp flag profiling=1. This
corrects the resulting mulitple defintion error:
../../talk/base/profiler.h:61:9: error: 'ENABLE_PROFILING' macro redefined [-Werror]
#define ENABLE_PROFILING
and allows us to use profiling=1 in standalone builds.
TESTED=build passes with profiling=1
R=wu@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/10829004
git-svn-id: http://webrtc.googlecode.com/svn/trunk@5804 4adac7df-926f-26a2-2b94-8c16560cd09d