f8dd7b10 fixed unnecessary shader compiles, but introduced a draw
call perf regression. Fix the regression robustly by storing a
minimal set of input layout elements/vertex attribute info,
but also handle the case where the vector sizes mismatch between
a cached and new vertex layout.

BUG=510151

Change-Id: If5e9ea4a4c9edaa7a78c8daa44bbe7d9927dc4e4
Reviewed-on: https://chromium-review.googlesource.com/292390Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>