Webgl test WebglConformance_conformance_extensions_webgl_compressed_texture_s3tc failed (once in 200 runs) on Linux Nvidia FYI.

This issue looks similar to  https://crbug.com/906066  in that there's some kind of swizzle issue. 

[62/139] gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_conformance_extensions_webgl_compressed_texture_s3tc failed unexpectedly 6.6117s:
  
  Traceback (most recent call last):
    _RunGpuTest at content/test/gpu/gpu_tests/gpu_integration_test.py:155
      self.RunActualGpuTest(url, *args)
    RunActualGpuTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:190
      getattr(self, test_name)(test_path, *args[1:])
    _RunConformanceTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:210
      self._CheckTestCompletion()
    _CheckTestCompletion at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:206
      self.fail(self._WebGLTestMessages(self.tab))
    fail at .swarming_module/lib/python2.7/unittest/case.py:410
      raise self.failureException(msg)
  AssertionError: texture should be initialized to black
  at (0, 3) expected: 0,0,0,255 was 0,0,0,0
  FAIL texture should be initialized to black
  at (0, 3) expected: 0,0,0,255 was 0,0,0,0
  
  Locals:
    msg : u'texture should be initialized to black\nat (0, 3) expected: 0,0,0,255 was 0,0,0,0\nFAIL texture should be initialized to black\nat (0, 3) expected: 0,0,0,255 was 0,0,0,0\n'
  
  No path to crashpad_database_util found
  No minidump found via crashpad_database_util
  Restarting browser due to unexpected test failure
  Closing browser (pid=10088) ...
  Failed to gracefully shutdown.
  Proceed to kill the browser.
  Browser is closed.
  Chrome Env: {'MANDATORY_PATH': '/usr/share/gconf/gnome-fallback.mandatory.path', 'XDG_GREETER_DATA_DIR': '/var/lib/lightdm-data/chrome-bot', 'GNOME_DESKTOP_SESSION_ID': 'this-is-deprecated', 'CHROME_HEADLESS': '1', 'XDG_CURRENT_DESKTOP': 'Unity', 'XDG_VTNR': '7', 'GTEST_TOTAL_SHARDS': '20', 'QT_IM_MODULE': 'ibus', 'LOGNAME': 'chrome-bot', 'USER': 'chrome-bot', 'GNOME_KEYRING_CONTROL': '/run/user/1000/keyring-SUXDRB', 'BOTO_CONFIG': '/home/chrome-bot/.boto', 'PATH': '/b/s/w/ir/.swarming_module_cache/vpython/cfc588/bin:/b/s/w/ir/.swarming_module:/b/s/w/ir/.swarming_module/bin:/b/s/cipd_cache/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/opt/dell/srvadmin/bin:/b/s/w/ir/.swarming_module_cache/vpython/cfc588/lib/python2.7/site-packages/cv2', 'SWARMING_BOT_ID': 'build894-m4', 'DISPLAY': ':0', 'LANG': 'en_US.UTF-8', 'VIRTUAL_ENV': '/b/s/w/ir/.swarming_module_cache/vpython/cfc588', 'SHELL': '/bin/bash', 'XDG_SESSION_PATH': '/org/freedesktop/DisplayManager/Session0', 'XAUTHORITY': '/home/chrome-bot/.Xauthority', 'LANGUAGE': 'en_US:', 'SESSION_MANAGER': 'local/build894-m4.golo.chromium.org:@/tmp/.ICE-unix/2147,unix/build894-m4.golo.chromium.org:/tmp/.ICE-unix/2147', 'SHLVL': '0', 'CHROME_DEVEL_SANDBOX': '/opt/chromium/chrome_sandbox', 'QT_QPA_PLATFORMTHEME': 'appmenu-qt5', 'CLUTTER_IM_MODULE': 'xim', 'SWARMING_HEADLESS': '1', 'QT4_IM_MODULE': 'xim', 'JOB': 'dbus', 'SESSION': 'gnome-fallback', 'DESKTOP_AUTOSTART_ID': '103bdfc8929ac98510154230280343026600000021470005', 'PYTHONNOUSERSITE': '1', 'IM_CONFIG_PHASE': '1', 'LUCI_CONTEXT': '/b/s/w/itoWPD3j/luci_ctx._4RYfB.json', 'GPG_AGENT_INFO': '/run/user/1000/keyring-SUXDRB/gpg:0:1', 'HOME': '/home/chrome-bot', 'CIPD_CACHE_DIR': '/b/s/cipd_cache/cache', 'SELINUX_INIT': 'YES', 'GIO_LAUNCHED_DESKTOP_FILE': '/home/chrome-bot/.config/autostart/swarming.desktop', 'XDG_RUNTIME_DIR': '/run/user/1000', 'GTK_IM_MODULE': 'ibus', 'PYTHONPATH': '/b/s/w/ir/third_party/catapult/telemetry', 'SESSIONTYPE': 'gnome-session', 'GTEST_SHARD_INDEX': '0', 'VPYTHON_VIRTUALENV_ROOT': '/b/s/w/ir/.swarming_module_cache/vpython', 'GDMSESSION': 'gnome-fallback', 'XMODIFIERS': '@im=ibus', 'DEFAULTS_PATH': '/usr/share/gconf/gnome-fallback.default.path', 'TEXTDOMAINDIR': '/usr/share/locale/', 'NO_GCE_CHECK': 'False', 'GIO_LAUNCHED_DESKTOP_FILE_PID': '2448', 'XDG_SEAT_PATH': '/org/freedesktop/DisplayManager/Seat0', 'LC_ALL': 'en_US.UTF-8', 'XDG_SESSION_ID': 'c2', 'DBUS_SESSION_BUS_ADDRESS': 'unix:abstract=/tmp/dbus-DKSOi2IuGx', 'TMPDIR': '/b/s/w/itoWPD3j', 'SWARMING_SERVER': 'https://chromium-swarm.appspot.com', 'SWARMING_TASK_ID': '413152ff50c48211', 'DESKTOP_SESSION': 'gnome-fallback', 'SSH_AUTH_SOCK': '/run/user/1000/keyring-SUXDRB/ssh', 'XDG_CONFIG_DIRS': '/etc/xdg/xdg-gnome-fallback:/usr/share/upstart/xdg:/etc/xdg', 'GNOME_KEYRING_PID': '2103', 'CIPD_PROTOCOL': 'v2', 'GDM_LANG': 'en_US', 'GTK_MODULES': 'overlay-scrollbar:unity-gtk-module', 'UPSTART_SESSION': 'unix:abstract=/com/ubuntu/upstart-session/1000/1934', 'INSTANCE': '', 'PWD': '/home/chrome-bot', 'TEXTDOMAIN': 'im-config', 'XDG_MENU_PREFIX': 'gnome-', 'LC_MESSAGES': 'en_US.UTF-8', 'XDG_DATA_DIRS': '/usr/share/gnome-fallback:/usr/share/gnome:/usr/local/share/:/usr/share/', 'BREAKPAD_DUMP_LOCATION': '/b/s/w/itoWPD3j/tmpcst3Oc', 'XDG_SEAT': 'seat0'}
  Starting Chrome ['/b/s/w/ir/out/Release/chrome', '--use-gl=angle', '--disable-gpu-watchdog', '--enable-experimental-web-platform-features', '--use-angle=gl', '--disable-gpu-process-for-dx12-vulkan-info-collection', '--disable-domain-blocking-for-3d-apis', '--test-type=gpu', '--disable-gpu-process-crash-limit', '--use-cmd-decoder=passthrough', '--disable-blink-features=WebXR', '--js-flags=--expose-gc', '--enable-logging=stderr', '--autoplay-policy=no-user-gesture-required', '--disable-features=UseSurfaceLayerForVideo', '--enable-net-benchmarking', '--metrics-recording-only', '--no-default-browser-check', '--no-first-run', '--ignore-background-tasks', '--enable-gpu-benchmarking', '--deny-permission-prompts', '--autoplay-policy=no-user-gesture-required', '--disable-background-networking', '--disable-component-extensions-with-background-pages', '--disable-default-apps', '--disable-search-geolocation-disclosure', '--proxy-server=socks://localhost:59278', '--proxy-bypass-list=<-loopback>', '--remote-debugging-port=0', '--enable-crash-reporter-for-testing', '--disable-component-update', '--window-size=1280,1024', '--user-data-dir=/b/s/w/itoWPD3j/tmpVPrj6Y', 'about:blank']
  DoNothingForwarder started between 127.0.0.1:35890 and 35890
  Browser started (pid=10294).
  OS: linux ubuntu
  Browser command line: /b/s/w/ir/out/Release/chrome --use-gl=angle --disable-gpu-watchdog --enable-experimental-web-platform-features --use-angle=gl --disable-gpu-process-for-dx12-vulkan-info-collection --disable-domain-blocking-for-3d-apis --test-type=gpu --disable-gpu-process-crash-limit --use-cmd-decoder=passthrough --disable-blink-features=WebXR --js-flags=--expose-gc --enable-logging=stderr --autoplay-policy=no-user-gesture-required --disable-features=UseSurfaceLayerForVideo --enable-net-benchmarking --metrics-recording-only --no-default-browser-check --no-first-run --ignore-background-tasks --enable-gpu-benchmarking --deny-permission-prompts --autoplay-policy=no-user-gesture-required --disable-background-networking --disable-component-extensions-with-background-pages --disable-default-apps --disable-search-geolocation-disclosure --proxy-server=socks://localhost:59278 --proxy-bypass-list=<-loopback> --remote-debugging-port=0 --enable-crash-reporter-for-testing --disable-component-update --window-size=1280,1024 --user-data-dir=/b/s/w/itoWPD3j/tmpVPrj6Y --flag-switches-begin --flag-switches-end --file-url-path-alias=/gen=/b/s/w/ir/out/Release/gen about:blank
  GPU device 0: VENDOR = 0x10de (Google Inc.), DEVICE = 0x1cb3 (ANGLE (NVIDIA Corporation Quadro P400/PCIe/SSE2 OpenGL 4.5 core))
  GPU Attributes:
    amd_switchable      : False
    can_support_threaded_texture_mailbox: False
    direct_rendering    : True
    gl_extensions       : GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_memory_size GL_ANGLE_multi_draw GL_ANGLE_multiview_multisample GL_ANGLE_program_cache_control GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_rectangle GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_texture GL_CHROMIUM_framebuffer_mixed_samples GL_CHROMIUM_path_rendering GL_CHROMIUM_sync_query GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_multisample_compatibility GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_sRGB_write_control GL_EXT_shader_texture_lod GL_EXT_texture_compression_bptc GL_EXT_texture_compression_dxt1 GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_sRGB_decode GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_NV_fence GL_NV_pack_subimage GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_fbo_render_mipmap GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_border_clamp GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture 
    gl_renderer         : ANGLE (NVIDIA Corporation Quadro P400/PCIe/SSE2 OpenGL 4.5 core)
    gl_reset_notification_strategy: 33362
    gl_vendor           : Google Inc.
    gl_version          : OpenGL ES 2.0 (ANGLE 2.1.0.666818eacf79)
    gl_ws_extensions    : EGL_EXT_create_context_robustness EGL_KHR_create_context EGL_KHR_get_all_proc_addresses EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled EGL_ANDROID_blob_cache 
    gl_ws_vendor        : 
    gl_ws_version       : 1.4 (ANGLE 2.1.0.666818eacf79)
    in_process_gpu      : False
    initialization_time : 0.065491
    jpeg_decode_accelerator_supported: False
    max_msaa_samples    : 8
    oop_rasterization_supported: True
    optimus             : False
    passthrough_cmd_decoder: True
    pixel_shader_version: 1.00
    process_crash_count : 0
    rgba_visual         : 0
    sandboxed           : True
    software_rendering  : False
    system_visual       : 0
    vertex_shader_version: 1.00
    video_decode_accelerator_flags: 0
  Feature Status:
    2d_canvas           : enabled
    flash_3d            : enabled
    flash_stage3d       : enabled
    flash_stage3d_baseline: enabled
    gpu_compositing     : enabled
    multiple_raster_threads: enabled_on
    native_gpu_memory_buffers: disabled_software
    oop_rasterization   : disabled_off
    protected_video_decode: unavailable_off
    rasterization       : disabled_software
    skia_deferred_display_list: disabled_off
    skia_renderer       : disabled_off
    surface_control     : disabled_off
    surface_synchronization: enabled_on
    video_decode        : unavailable_off
    viz_display_compositor: enabled_on
    webgl               : enabled
    webgl2              : enabled
  Driver Bug Workarounds:
    clear_uniforms_before_first_program_use
    disable_framebuffer_cmaa
    scalarize_vec_and_mat_constructor_args
    disabled_extension__gl__khr_blend_equation_advanced
    disabled_extension__gl__khr_blend_equation_advanced_coherent
  Traceback (most recent call last):
    File "/b/s/w/ir/third_party/catapult/telemetry/telemetry/testing/serially_executed_browser_test_case.py", line 214, in <lambda>
      return lambda self: based_method(self, *args)
    File "/b/s/w/ir/content/test/gpu/gpu_tests/gpu_integration_test.py", line 155, in _RunGpuTest
      self.RunActualGpuTest(url, *args)
    File "/b/s/w/ir/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 190, in RunActualGpuTest
      getattr(self, test_name)(test_path, *args[1:])
    File "/b/s/w/ir/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 210, in _RunConformanceTest
      self._CheckTestCompletion()
    File "/b/s/w/ir/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 206, in _CheckTestCompletion
      self.fail(self._WebGLTestMessages(self.tab))
  AssertionError: texture should be initialized to black
  at (0, 3) expected: 0,0,0,255 was 0,0,0,0
  FAIL texture should be initialized to black
  at (0, 3) expected: 0,0,0,255 was 0,0,0,0
  
DevTools console [network]: Failed to load resource: the server responded with a status of 404 (File not found) http://127.0.0.1:57730/favicon.ico
WebglConformance_conformance_glsl_bugs_assign_to_swizzled_twice_in_function was expected to fail, but passed.