gpu, cmaa: add glApplyScreenSpaceAntialiasingCHROMIUM unittests

Add new unittests for glApplyScreenSpaceAntialiasingCHROMIUM, which check the
conformance with GL_INTEL_framebuffer_CMAA spec [1].

Many tests are very similar to tests of GLCopyTextureCHROMIUMTest.

[1] https://www.khronos.org/registry/gles/extensions/INTEL/framebuffer_CMAA.txt

BUG=535198
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2432413003
Cr-Commit-Position: refs/heads/master@{#427326}
4 files changed