glmark2 is a an OpenGL ES 2.0 benchmark licensed under GPL v3.
See https://github.com/glmark2/glmark2

ANGLE can use glmark2 as a metric and guide for optimization. It will
add a number of useful performance tests. This CL adds the initial
build integration.

A follow-up CL will integrate glmark2 into our performance tests. Note
that glmark2 will not be shipped with Chrome or Android. It will only
be used on our test infrastructure.

Note that the data path solution is temporary. When integrated into
ANGLE we will make sure we CWD into the glmark2 directory before
running the benchmark.

Bug: angleproject:3139
Change-Id: I5c4f605221c255ab19abd10b321b5867ab459105
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1449984
Commit-Queue: Jamie Madill <jmadill@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>