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.

Reland with fix for comparison warning.

BUG=510151

Change-Id: I578ddbb5b5bb12e7c1a901f23c7b5fcbd64b5d23
Reviewed-on: https://chromium-review.googlesource.com/292460Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>