Add interface to system trace clock.
Add TimeTicks::NowFromSystemTraceTime to return the current system trace
event clock (falling back to TimeTicks::HighResNow when not supported).
On systems where the system trace clock is available this allows
system and chrome events to be stamped with a common clock (eliminating
post-processing time shift adjustment that can be hard).
BUG=chromium-os:27809
TEST=unit tests + collect trace data on chrome os w/ kernel that supports clock_gettime(CLOCK_SYSTEM_TRACE)
Change-Id: Ia6a500bd13a6f09c49052a1dd1421027960d8dea
Review URL: http://codereview.chromium.org/10257020
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134772 0039d316-1c4b-4281-b951-d872f2087c98
CrOS-Libchrome-Original-Commit: 190f13f73accbebd0e715c9f09db2f1c42b582ca
4 files changed