Remove unused time variables
Remove unused time variables

BUG=None
TEST=None

Review URL: https://codereview.chromium.org/2487603002 .

lemenkov/libyuv,lemenkov/libyuv,yarrcc/libyuv-ios,lemenkov/libyuv,yarrcc/libyuv-ios,yarrcc/libyuv-ios,lemenkov/libyuv,yarrcc/libyuv-ios