We always read out of bounds here.  Fix that.

Turns out the comment wasn't lying!

BUG=
R=bungeman@google.com

Review URL: https://codereview.chromium.org/58473002

git-svn-id: http://skia.googlecode.com/svn/trunk/src@12123 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed