cleanup stale comment I left in accidentally

Bug: 986808
No-Try: True
Change-Id: Ic6460697f1f64f822c550ad21ae04700446116d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1783107
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Auto-Submit: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#692872}

content/test/gpu/gpu_tests/test_expectations/webgl_conformance_expectations.txt

@@ -549,9 +549,6 @@ crbug.com/995652 [ android ] conformance/uniforms/out-of-bounds-uniform-array-ac
 crbug.com/981579 [ android opengles ] conformance/textures/misc/tex-video-using-tex-unit-non-zero.html [ RetryOnFailure ]
 crbug.com/906724 [ android opengles ] conformance/textures/video/tex-2d-luminance_alpha-luminance_alpha-unsigned_byte.html [ Failure ]
 crbug.com/906724 [ android opengles ] conformance/textures/video/tex-2d-luminance-luminance-unsigned_byte.html [ Failure ]
-# TODO(crbug.com/979444, crbug.com/986808): once this is passing on
-# the passthrough command decoder, simplify the RetryOnFailure
-# expectation at the top of this file to just not declare any OS.
 
 # Misc failures
 crbug.com/angleproject/2988 [ android opengles ] conformance/context/context-size-change.html [ Failure ]