The oil may not be going to Japan and China but I'll bet it ends up in Europe or Latin America or maybe even India. The Canadians CAN'T build a pipeline to their coast since the provincial government of British Columbia has rejected all possible proposals to do so because of the environmental risks.
Most of the oil transported by the Keystone Pipeline will never end-up in the tanks of American cars. In fact, it could result in LESS Canadian oil going to US refineries since now it will be going to Texas instead of where it's going now. Remember, there already are pipelines carrying Canadian oil in the States, just that the oil is going to mid-West refineries where it actually does end-up being sold to American drivers. But once the new pipeline running directly to Texas is completed, the oil will be diverted to the new pipeline and those mid-Western refineries will be cut-off as it will much more profitable to refine the oil in Texas and then immediately ship it overseas. And to add insult onto injury, the federal government will not even be able to collect a dime of taxes from those extra profits earned by either the pipeline operators or the refinery owners in Texas since the oil will technically never be considered as actually BEING in the United States. In fact since virtually all of the oil will now be considered tax exempt, the US is actually going LOSE tax revenues. At least when that Canadian oil was being refined in the mid-West and sold locally, the profits earned were taxable, but that will all change once the new pipeline is finished since it goes into the pipeline in Canada, a foreign country, and comes out in a refinery in Texas which will be inside a so-called 'free-trade zone' and since the distilled products are going to leave the country in tankers, it will be as if the oil was never really here. Not a bad deal if you can get it, eh?
http://switchboard.nrdc.org/blogs/aswift/keystone_xl_is_a_tar_sands_pip.html
http://billingsgazette.com/news/state-and-regional/montana/keystone-pipeline-would-oil-be-consumed-in-the-u-s/article_f2e54343-51ba-57e7-89bd-a2656901ba62.html
http://www.thedailybeast.com/articles/2012/03/03/do-republicans-realize-that-keystone-pipeline-won-t-bring-gas-to-u-s.html