Re-add (curiously) missing 'return' statement to differ_unittest.
Re-add (curiously) missing 'return' statement to differ_unittest.

BUG=none
TEST=unittests on Windows

Review URL: http://codereview.chromium.org/2772002

git-svn-id: http://src.chromium.org/svn/trunk/src@49349 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 52212aac229551476c3f16c09c8043bbc4ff04d1
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser