Correct subImage uses of texture type -> target. Texture "types" are the same as texture "targets" except for cube maps. Cube map targets specify a single face. Cube map types specify a whole cube map. The subImage functions should take a target instead of a type. We were using both in different places. This CL corrects all uses in subImage calls to "target". It also adds a helper for getting a target texture from a target. And clarifies the naming of the texture query methods. Bug: angleproject:3356 Change-Id: I06eb5c5666eec9b8934becf2ba57a066d5cdabde Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1558672 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>