Add support for unsigned int32 in string_number_conversions

BUG=

Review URL: https://codereview.chromium.org/26131003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230396 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed