Who's country brought the veto to the UNSC? Oh yes, America. But it is not only for America's use. It's for any member to use if they feel that a resolution is being crammed through. Russia and China would not abstain after what happened in Libya, where the agenda was to see the end of Ghadaffi. Just as the agenda here is to see the end of Assad.
India withdraws order to block Internet pornography sites (Reuters)
from the article: Syrian forces kill over 300 in Homs; China and Russia veto UN resolution