Well, that's interesting.  For one thing, it looks like this used to work in M66 (tested on jawag's machine).  Also, this just uses the same code path (ui::SelectFileDialog::SelectFile) on all OS's, so this strikes me as an issue with our file picking in CrOS.

Can we do a bisect on this to see when it regressed?

This also seems like something that should be a blocker, since loading unpacked extensions is pretty important to developers.  Adding label.

Couldn't run bisect on my machine for chromeos :-( I keep getting "aww, snap!"

I am also getting same error for any WebUI page when I try to bisect builds. FWIW this is the command I used.

./tools/bisect-builds.py -a chromeos -b 562893 -g 560893  --use-local-cache -- --user-data-dir=/tmp/debug_chromeos

Adding FileManager component in case this is related.

Quick note: when packing an extension both the file picker and the folder picker seem to work as expected

@sashab could you help determine if this is related to any FileManager changes?

Could this be related to the change at https://bugs.chromium.org/p/chromium/issues/detail?id=772180?

@aee: Can you provide a bit more context? Why is miu@ the appropriate owner for this bug?

miu@ has a fix for this here https://chromium-review.googlesource.com/c/chromium/src/+/1089877

Note that we will nee to merge the fix to M68, so as long as https://chromium-review.googlesource.com/c/chromium/src/+/1089877 is likely to be approved for a merge, SGTM. Otherwise, we need a smaller fix just to revert CrOS back to the old behavior, and merge that one to M68.

bisect-builds.py doesn't work for chromeos (see issue 663450).

When I try click "Open Unpacked" on ToT, I get a DCHECK failure:

[89194:89194:0607/095923.616878:FATAL:url_util.cc(60)] Check failed: false. 
#0 0x7f1db69808fc base::debug::StackTrace::StackTrace()
#1 0x7f1db68d030b logging::LogMessage::~LogMessage()
#2 0x561d37834f50 file_manager::util::GetFileManagerMainPageUrlWithParams()
#3 0x561d38f10160 SelectFileDialogExtension::SelectFileImpl()
#4 0x7f1db10db0d3 ui::SelectFileDialog::SelectFile()
#5 0x561d386454f9 extensions::api::EntryPicker::EntryPicker()
#6 0x561d3863d6c1 extensions::api::DeveloperPrivateLoadUnpackedFunction::Run()
#7 0x561d371fae82 ExtensionFunction::RunWithValidation()
#8 0x561d371fcdad extensions::ExtensionFunctionDispatcher::DispatchWithCallbackInternal()
#9 0x561d371fca4b extensions::ExtensionFunctionDispatcher::Dispatch()
#10 0x561d3722150a extensions::ExtensionWebContentsObserver::OnRequest()
#11 0x561d37221389 _ZN3IPC8MessageTI29ExtensionHostMsg_Request_MetaNSt3__15tupleIJ31ExtensionHostMsg_Request_ParamsEEEvE8DispatchIN10extensions28ExtensionWebContentsObserverES9_N7content15RenderFrameHostEMS9_FvPSB_RKS4_EEEbPKNS_7MessageEPT_PT0_PT1_T2_
#12 0x561d372212d2 extensions::ExtensionWebContentsObserver::OnMessageReceived()
#13 0x561d3858b291 extensions::ChromeExtensionWebContentsObserver::OnMessageReceived()
#14 0x7f1db3fc5292 content::WebContentsImpl::OnMessageReceived()
#15 0x7f1db3c6fcf4 content::RenderFrameHostImpl::OnMessageReceived()
#16 0x7f1db3e8602b content::RenderProcessHostImpl::OnMessageReceived()
#17 0x7f1db5b32b41 IPC::ChannelProxy::Context::OnDispatchMessage()
#18 0x7f1db5b3566b _ZN4base8internal7InvokerINS0_9BindStateIMN3IPC12ChannelProxy7ContextEFvRKNS3_7MessageEEJ13scoped_refptrIS5_ES6_EEEFvvEE3RunEPNS0_13BindStateBaseE
#19 0x7f1db68b32c5 base::debug::TaskAnnotator::RunTask()
#20 0x7f1db68dcaf9 base::internal::IncomingTaskQueue::RunTask()
#21 0x7f1db68e015b base::MessageLoop::RunTask()
#22 0x7f1db68e04ea base::MessageLoop::DeferOrRunPendingTask()
#23 0x7f1db68e074c base::MessageLoop::DoWork()
#24 0x7f1db69a0969 base::MessagePumpLibevent::Run()
#25 0x7f1db68dfb44 base::MessageLoop::Run()
#26 0x7f1db6912449 base::RunLoop::Run()
#27 0x561d37c2bfeb ChromeBrowserMainParts::MainMessageLoopRun()
#28 0x7f1db3afb417 content::BrowserMainLoop::RunMainMessageLoopParts()
#29 0x7f1db3afe0b6 content::BrowserMainRunnerImpl::Run()
#30 0x7f1db3af76c4 content::BrowserMain()
#31 0x7f1db4523033 content::RunBrowserProcessMain()
#32 0x7f1db4523fbd content::ContentMainRunnerImpl::Run()
#33 0x7f1db6c338cc service_manager::Main()
#34 0x7f1db4522054 content::ContentMain()
#35 0x561d37059ee3 ChromeMain
#36 0x7f1da89ef2b1 __libc_start_main
#37 0x561d37059d5a _start

Received signal 6
#0 0x7f1db69808fc base::debug::StackTrace::StackTrace()
#1 0x7f1db69803f1 base::debug::(anonymous namespace)::StackDumpSignalHandler()
#2 0x7f1daa0b40c0 <unknown>
#3 0x7f1da8a01fcf gsignal
#4 0x7f1da8a033fa abort
#5 0x7f1db697f285 base::debug::BreakDebugger()
#6 0x7f1db68d06c8 logging::LogMessage::~LogMessage()
#7 0x561d37834f50 file_manager::util::GetFileManagerMainPageUrlWithParams()
#8 0x561d38f10160 SelectFileDialogExtension::SelectFileImpl()
#9 0x7f1db10db0d3 ui::SelectFileDialog::SelectFile()
#10 0x561d386454f9 extensions::api::EntryPicker::EntryPicker()
#11 0x561d3863d6c1 extensions::api::DeveloperPrivateLoadUnpackedFunction::Run()
#12 0x561d371fae82 ExtensionFunction::RunWithValidation()
#13 0x561d371fcdad extensions::ExtensionFunctionDispatcher::DispatchWithCallbackInternal()
#14 0x561d371fca4b extensions::ExtensionFunctionDispatcher::Dispatch()
#15 0x561d3722150a extensions::ExtensionWebContentsObserver::OnRequest()
#16 0x561d37221389 _ZN3IPC8MessageTI29ExtensionHostMsg_Request_MetaNSt3__15tupleIJ31ExtensionHostMsg_Request_ParamsEEEvE8DispatchIN10extensions28ExtensionWebContentsObserverES9_N7content15RenderFrameHostEMS9_FvPSB_RKS4_EEEbPKNS_7MessageEPT_PT0_PT1_T2_
#17 0x561d372212d2 extensions::ExtensionWebContentsObserver::OnMessageReceived()
#18 0x561d3858b291 extensions::ChromeExtensionWebContentsObserver::OnMessageReceived()
#19 0x7f1db3fc5292 content::WebContentsImpl::OnMessageReceived()
#20 0x7f1db3c6fcf4 content::RenderFrameHostImpl::OnMessageReceived()
#21 0x7f1db3e8602b content::RenderProcessHostImpl::OnMessageReceived()
#22 0x7f1db5b32b41 IPC::ChannelProxy::Context::OnDispatchMessage()
#23 0x7f1db5b3566b _ZN4base8internal7InvokerINS0_9BindStateIMN3IPC12ChannelProxy7ContextEFvRKNS3_7MessageEEJ13scoped_refptrIS5_ES6_EEEFvvEE3RunEPNS0_13BindStateBaseE
#24 0x7f1db68b32c5 base::debug::TaskAnnotator::RunTask()
#25 0x7f1db68dcaf9 base::internal::IncomingTaskQueue::RunTask()
#26 0x7f1db68e015b base::MessageLoop::RunTask()
#27 0x7f1db68e04ea base::MessageLoop::DeferOrRunPendingTask()
#28 0x7f1db68e074c base::MessageLoop::DoWork()
#29 0x7f1db69a0969 base::MessagePumpLibevent::Run()
#30 0x7f1db68dfb44 base::MessageLoop::Run()
#31 0x7f1db6912449 base::RunLoop::Run()
#32 0x561d37c2bfeb ChromeBrowserMainParts::MainMessageLoopRun()
#33 0x7f1db3afb417 content::BrowserMainLoop::RunMainMessageLoopParts()
#34 0x7f1db3afe0b6 content::BrowserMainRunnerImpl::Run()
#35 0x7f1db3af76c4 content::BrowserMain()
#36 0x7f1db4523033 content::RunBrowserProcessMain()
#37 0x7f1db4523fbd content::ContentMainRunnerImpl::Run()
#38 0x7f1db6c338cc service_manager::Main()
#39 0x7f1db4522054 content::ContentMain()
#40 0x561d37059ee3 ChromeMain
#41 0x7f1da89ef2b1 __libc_start_main
#42 0x561d37059d5a _start
  r8: 0000000000000000  r9: 00007fff82f0aae0 r10: 0000000000000008 r11: 0000000000000246
 r12: 00007fff82f0b1e8 r13: 00007fff82f0b1d8 r14: 00007fff82f0b1e0 r15: 00007fff82f0b181
  di: 0000000000000002  si: 00007fff82f0aae0  bp: 00007fff82f0ad20  bx: 0000000000000006
  dx: 0000000000000000  ax: 0000000000000000  cx: 00007f1da8a01fcf  sp: 00007fff82f0ab58
  ip: 00007f1da8a01fcf efl: 0000000000000246 cgf: 002b000000000033 erf: 0000000000000000
 trp: 0000000000000000 msk: 0000000000000000 cr2: 0000000000000000
[end of stack trace]
Calling _exit(1). Core file will not be generated.

Who owns the code for the File Picker dialog (the native part)? Is that the files team or Chrome Browser UI team?