This is a follow-up CL for
https://chromium-review.googlesource.com/c/544634/.
In this commit, we add drawElements perf test for d3d9, d3d11 and
OpenGL. Specially, we test DrawElements with unchanged index buffer
every frame and changed index buffer every frame. This is also a
preparation for further remove IndexRange in validation.
Paste a set of data (repeated 30) for reference on Intel skylake
Win10 desktop.
DrawElementsPerfBenchmark.Run/d3d11:
mean: 13186.1666667, stddev: 200.479605502,
truncated mean: 13192.5416667, stddev: 156.284190704
DrawElementsPerfBenchmark.Run/d3d11_index_buffer_changed:
mean: 43.6, stddev: 4.02160830183,
truncated mean: 43.5833333333, stddev: 2.97092391166

BUG=angleproject:1393
TEST=angle_perftests

Change-Id: I94bd181aa2b4515df1affc79f591f5db399feac3
Reviewed-on: https://chromium-review.googlesource.com/585981
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>