On issue 734978, oshima@ reports:
I sync'ed today and Chome stopped booting (did re-sync 10 min ago but no luck)
I thought it's   crbug.com/736807  , but my image is newer than that.

(Cave R61-9691.0.0 + ToT)

[18522:18582:0627/183308.911072:ERROR:validation_errors.cc(76)] Invalid message: VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE (invalid handle or interface ID in array expecting valid handles or interface IDs: array size - 1; index - 0)
[18522:18582:0627/183308.911138:ERROR:browser_child_process_host_impl.cc(588)] Terminating child process for bad Mojo message: Received bad user message: Validation failed for GpuService ResponseValidator [VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE (invalid handle or interface ID in array expecting valid handles or interface IDs: array size - 1; index - 0)]
libva info: VA-API version 0.39.2
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib64/va/drivers/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_39
libva info: va_openDriver() returns 0
[18522:18582:0627/183308.966356:ERROR:validation_errors.cc(76)] Invalid message: VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE (invalid handle or interface ID in array expecting valid handles or interface IDs: array size - 1; index - 0)
[18522:18582:0627/183308.966411:ERROR:browser_child_process_host_impl.cc(588)] Terminating child process for bad Mojo message: Received bad user message: Validation failed for GpuService ResponseValidator [VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE (invalid handle or interface ID in array expecting valid handles or interface IDs: array size - 1; index - 0)]
libva info: VA-API version 0.39.2
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib64/va/drivers/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_39
libva info: va_openDriver() returns 0