Bug 217761

Description: webgl/2.0.0/conformance/extensions/webgl-compressed-texture-s3tc-srgb.html The first crash that I see this on the dashboard was 08/31/20 at r266366 and continued to flaky crash until 09/04/20 at r266624 where it began passing consistently. Then at 09/07/20 at r266714 the flaky crash began again and ended 09/09/20 at r266799. There is another period of consistent passing from 09/09/20 until 10/06/20 at r268052 where the flaky crash begins again until present. I can reproduce this on r267662, but unable to reproduce on 267661. Commit r267662 has to do with updating the names everywhere and URLs in IDLAttributes.json, which could have introduced the flaky crash. The change was introduced here https://trac.webkit.org/changeset/266662/webkit. REPRODUCTION STEPS Command: run-webkit-tests --exit-after-n-failures 1 --exit-after-n-crashes-or-timeouts 1 --iterations 50 --no-retry --force --no-build -f --debug -1 webgl/2.0.0/conformance/extensions/webgl-compressed-texture-s3tc-srgb.html Result: Regressions: Unexpected crashes (1) webgl/2.0.0/conformance/extensions/webgl-compressed-texture-s3tc-srgb.html [ Crash ] History: https://results.webkit.org/?suite=layout-tests&test=webgl%2F2.0.0%2Fconformance%2Fextensions%2Fwebgl-compressed-texture-s3tc-srgb.html&platform=mac&style=debug&flavor=wk1&limit=50000 Crash Log: Application Specific Information: CRASHING TEST: webgl/2.0.0/conformance/extensions/webgl-compressed-texture-s3tc-srgb.html Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 com.apple.JavaScriptCore 0x00000001105ac4fe WTFCrash + 14 (Assertions.cpp:295) 1 com.apple.WebCore 0x000000012ad8ea6b WTFCrashWithInfo(int, char const*, char const*, int) + 27 2 com.apple.WebCore 0x000000012eb373f9 WebCore::FrameView::paintContents(WebCore::GraphicsContext&, WebCore::IntRect const&, WebCore::Widget::SecurityOriginPaintPolicy, WebCore::EventRegionContext*) + 697 (FrameView.cpp:4292) 3 com.apple.WebKitLegacy 0x000000011c5f03e9 -[WebFrame(WebInternal) _drawRect:contentsOnly:] + 1417 (WebFrame.mm:657) 4 com.apple.WebKitLegacy 0x000000011c614ff6 -[WebHTMLView drawSingleRect:] + 774 (WebHTMLView.mm:3883) 5 com.apple.WebKitLegacy 0x000000011c615711 -[WebHTMLView drawRect:] + 625 (WebHTMLView.mm:3954)