return early from ProcessRawBytesWithSeperators() when data length is 0

BUG=109717
TEST=N/A
Review URL: http://codereview.chromium.org/9169028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117241 0039d316-1c4b-4281-b951-d872f2087c98