This is only a renaming: change VertexInput to VertexBuffer, and
change InputState to VertexInput.
The next two patches will do as follows:
1) change the structure of vertex input descriptor related stuff.
2) change num to count.
BUG=dawn:80, dawn:107
Change-Id: Ie76aa653a527759a9c3b4a4792e3254689f053b8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/7420
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Yunchao He <yunchao.he@intel.com>