Bug 223351

https://www.khronos.org/registry/webgl/sdk/tests/conformance2/rendering/rasterizer-discard-and-implicit-clear.html?webglVersion=2&quiet=0&quick=1 Enabling RASTERIZER_DISCARD should not affect implicit clears On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS WebGL context creation succeeded Verify that draws with rasterizer discard enabled do not interfere with implicit clears FAIL left half of canvas should be clear at (0, 0) expected: 0,0,0,0 was 255,0,0,59 PASS right half of canvas should be green Verify that readPixels with rasterizer discard enabled receives implicitly cleared data PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS should be 0,0,0,0 PASS successfullyParsed is true TEST COMPLETE

At least macOS 11.3, iMacPro1,1, Radeon Pro Vega 56

<rdar://problem/75774254>

Committed r295490 (251495@main): <https://commits.webkit.org/251495@main> Reviewed commits have been landed. Closing PR #1470 and removing active labels.