Refactor trace_inputs.py strace implementation to use -ff instead of -f.

So each process has its own log file, reducing the race conditions inside
strace.

R=mad@chromium.org
BUG=98636
TEST=


Review URL: https://chromiumcodereview.appspot.com/10356129

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137397 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed