Add timestamp logging

Add a new timer class that can be invoked for measuring time between
lines of code.  It uses the existing Utils::get_timestamp_us() function.

BUG=chromium-os:25587
TEST=glmark2 builds successfully.

Signed-off-by: Simon Que <sque@chromium.org>

Change-Id: I491998abac12322a8f1dc97dc792486dc6a55d1c
2 files changed