Blink will use this API to stream script data into V8 as the scripts
load. During loading, V8 can already parse the scripts. They will be then
compiled and executed when the loading is complete.

BUG=
R=jochen@chromium.org, rossberg@chromium.org, svenpanne@chromium.org, yangguo@chromium.org

Review URL: https://codereview.chromium.org/366153002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23865 ce2b1a6d-e550-0410-aec6-3dcde31c8c00