Adjusts the bench expectations calculation to consider average value.

BUG=skia:2225
NOTRY=true
R=borenet@google.com
TBR=borenet@google.com

Author: bensong@google.com

Review URL: https://codereview.chromium.org/231513002

git-svn-id: http://skia.googlecode.com/svn/trunk@14112 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed