Adds a function to update a level of a TextureStorage from another resource. TRAC #22210 Author: Shannon Woods Signed-off-by: Nicolas Capens Signed-off-by: Daniel Koch git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1651 736b8ea6-26fd-11df-bfd4-992fa37f6226