Updated the error handling of compressed image sizes based on the ANGLE_texture_compression_dxt spec. TRAC #13332 Signed-off-by: Jamie Madill Signed-off-by: Shannon Woods Author: Geoff Lang git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1975 736b8ea6-26fd-11df-bfd4-992fa37f6226