Correctly expand literal buffer for surrogate pairs.
Correctly expand literal buffer for surrogate pairs.

R=jkummerow@chromium.org
BUG=chromium:423212
LOG=Y

Review URL: https://codereview.chromium.org/652743005

git-svn-id: f98b9d40cb02301bc76fa9e1b46ee668158567fd@24603 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh