WebGL canvas tests fail on at least the Nexus 5X bots with error messages about missing fonts:

...
AssertionError: font missing
FAIL font missing
font missing
FAIL font missing
font missing
FAIL font missing
...

Tests:
conformance/extensions/oes-texture-float-with-canvas.html
conformance/extensions/oes-texture-half-float-with-canvas.html
conformance/textures/canvas/*

I cannot reproduce these failures locally on a Nexus 5X device with a different OS version than the bots.  These tests appeared to start failing when enabling GPU rasterization.

Example run with failures:
https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8928762788451829536/+/steps/webgl_conformance_gles_passthrough_tests_on_Android_device_Nexus_5X__with_patch_/0/stdout