Fix ToUnsigned for 4-byte wchar_t platforms.
Fix ToUnsigned for 4-byte wchar_t platforms.

git-svn-id: http://src.chromium.org/svn/trunk/src@712 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 33b0cd649cb6e5ea02475f42bf69379fa32ee772
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