Fixed a test where a method was expected to be called but it wasn't.

A recent optimization in the code made that second call unneeded as so
our expectation is not met anymore (for good so).

BUG=chromium-os:18430
TEST=Metrics unit tests should pass.

Change-Id: I1162dc657156ee9207b904ab544b0f151eec0453
Reviewed-on: http://gerrit.chromium.org/gerrit/5302


Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Tested-by: Julian Pastarmov <pastarmovj@chromium.org>