app_shell is an app runner, much like content_shell but for apps.

It DCHECKs on exit when --disable-gpu is specified (or when no GPU is available):

[136857:136865:0220/145637.889518:2732813702562:WARNING:discardable_shared_memory_manager.cc(436)] Some MojoDiscardableSharedMemoryManagerImpls are still alive. They will be leaked.
[136857:136857:0220/145637.893463:2732813706505:FATAL:server_shared_bitmap_manager.cc(71)] Check failed: handle_map_.empty().
#0 0x7f6056dcb54c base::debug::StackTrace::StackTrace()
#1 0x7f6056df578b logging::LogMessage::~LogMessage()
#2 0x7f604d53bdf8 viz::ServerSharedBitmapManager::~ServerSharedBitmapManager()
#3 0x7f604d53cf41 base::LazyInstance<>::OnExit()
#4 0x7f6056db683a base::AtExitManager::ProcessCallbacksNow()
#5 0x7f6056db65d5 base::AtExitManager::~AtExitManager()
#6 0x7f60565c51d1 content::ContentMainRunnerImpl::Shutdown()
#7 0x7f604c9de9d9 service_manager::Main()
#8 0x7f60565c3381 content::ContentMain()
#9 0x000000423151 main
#10 0x7f604dafff45 __libc_start_main
#11 0x00000042302a _start


Seems like some shared memory is not being freed. I suspect this is due to a larger problem in how app_shell starts up or exits, because I'm sure there are things content_shell does that app_shell doesn't.

To start investigating, I'm not sure if the issue really has to do with viz or mojo. I've CC'd some folks who might be knowledgeable -- can anyone provide any pointers?