Use dmesg rather than /var/log/messages, because it's faster, on average
Use dmesg rather than /var/log/messages, because it's faster, on average

When /var/log/messages is small, "dmesg | awk ..." requires more CPU
time than "awk ... /var/log/messages".  However, the messages file
grows substantially over time, so "dmesg" rapidly becomes cheaper,
and provides more consistent timing as well.

BUG=chromium-os:8755
TEST=platform_BootPerf

Review URL: http://codereview.chromium.org/4728001

Change-Id: If0de3074756f58a1d1f709671c9cd85980b85f59

joshfire/chromiumos-platform-init