Remove commented out conformance/extensions/ext-sRGB.html expectation

Has been commented out for a while, which means the test passes.

TBR=bsheedy

Bug: 679696
Change-Id: I39601b7d83535dcb91a9fa24fc61e43cb5f75f8b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441269Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812267}

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

@@ -276,8 +276,6 @@ crbug.com/630860 [ win nvidia ] conformance/textures/misc/texture-upload-size.ht
 crbug.com/1045339 [ win10 debug-x64 nvidia ] conformance/extensions/oes-texture-half-float-with-video.html [ Skip ]
 crbug.com/1109977 [ win nvidia passthrough ] conformance/glsl/misc/shader-with-non-reserved-words.html [ Skip ]
 
-# crbug.com/679696 [ win nvidia no_passthrough ] conformance/extensions/ext-sRGB.html [ Failure ]
-
 # Win10 / NVIDIA Quadro P400 / D3D11 failures
 crbug.com/898674 [ win10 nvidia-0x1cb3 d3d11 ] conformance/extensions/oes-texture-float-with-video.html [ RetryOnFailure ]