Some upstream changes broke the automatic fallback to SwiftShader.
Without this workaround the GPU initialization fails (apparently due to requiring Vulkan):
machine # libva error: vaGetDriverNameByIndex() failed with unknown libva error, driver_name = (null)
machine # [1001:1001:1101/104304.000625:ERROR:viz_main_impl.cc(161)] Exiting GPU process due to errors during initialization
machine # libva error: vaGetDriverNameByIndex() failed with unknown libva error, driver_name = (null)
machine # [1052:1052:1101/104305.060496:ERROR:viz_main_impl.cc(161)] Exiting GPU process due to errors during initialization
machine # [1084:1084:1101/104305.165898:ERROR:angle_platform_impl.cc(44)] Display.cpp:894 (initialize): ANGLE Display::initialize error 0: Internal Vulkan error (-3): Initialization of an object could not be completed for implementation-specific reasons, in ../../third_party/angle/src/libANGLE/renderer/vulkan/RendererVk.cpp, initialize:1048.
machine # [1084:1084:1101/104305.171191:ERROR:gl_surface_egl.cc(782)] EGL Driver message (Critical) eglInitialize: Internal Vulkan error (-3): Initialization of an object could not be completed for implementation-specific reasons, in ../../third_party/angle/src/libANGLE/renderer/vulkan/RendererVk.cpp, initialize:1048.
machine # [1084:1084:1101/104305.178707:ERROR:gl_surface_egl.cc(1382)] eglInitialize SwANGLE failed with error EGL_NOT_INITIALIZED
machine # [1084:1084:1101/104305.180111:ERROR:gl_ozone_egl.cc(20)] GLSurfaceEGL::InitializeOneOff failed.
machine # [1084:1084:1101/104305.189760:ERROR:viz_main_impl.cc(161)] Exiting GPU process due to errors during initialization
machine # [1092:1092:1101/104305.233470:ERROR:gpu_init.cc(457)] Passthrough is not supported, GL is disabled, ANGLE is
This workaround restores the previous result:
machine # [1004:1004:1101/104551.131190:ERROR:gpu_init.cc(457)] Passthrough is not supported, GL is swiftshader, ANGLE is
The workaround is only required for Chromium, not Google Chrome.
Some specialisations (such as those which affect various boot-time
attributes) cannot be switched to at runtime. This allows picking the
specialisation at boot time.
