[Telemetry]: Add Browsermark 2.0 benchmark suite.

TEST= tools/perf/run_benchmark --browser=system browsermark

Review URL: https://codereview.chromium.org/66513010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235544 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235544