[Telemetry] Reduce page cycler cycle time by about another 10% on android.
On my device, dumpsys meminfo takes about 900ms. cat /proc/meminfo gives us the
same data we need in about 40ms. This also has the nice benefit of sharing the
same implemenation as the other proc-supporting backends.
This reduces one iteration of moz from 4.5m -> <4m.
BUG=372489
Review URL: https://codereview.chromium.org/
284743005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270109 0039d316-1c4b-4281-b951-d872f2087c98