Browser totally crashes on Nightly 56.0ab1

[souri]

Version: Nightly 56.0a1 (2017-07-28) (64-bit)

1501497600612	addons.webextension.jid1-xUfzOsOFlzSOXg@jetpack	WARN	Please specify whether you want browser_style or not in your page_action options.
[Child 22199] ###!!! ABORT: LoadSheetSync failed with error 80520015 loading built-in stylesheet 'chrome://global/skin/scrollbars.css': file /home/worker/workspace/build/src/layout/style/nsLayoutStylesheetCache.cpp, line 776
[Child 22199] ###!!! ABORT: LoadSheetSync failed with error 80520015 loading built-in stylesheet 'chrome://global/skin/scrollbars.css': file /home/worker/workspace/build/src/layout/style/nsLayoutStylesheetCache.cpp, line 776
[Parent 22158] WARNING: pipe error (62): Connection reset by peer: file /home/worker/workspace/build/src/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 353

[paulofilip3]

Same for me!
Version: 56.0b2 (64-bit)

###!!! [Parent][MessageChannel] Error: (msgtype=0x140078,name=PBrowser::Msg_Destroy) Channel error: cannot send/recv

[Parent 23874] WARNING: waitpid failed pid:3611 errno:10: file /home/worker/workspace/build/src/ipc/chromium/src/base/process_util_posix.cc, line 276
[Child 8827] ###!!! ABORT: LoadSheetSync failed with error 80520015 loading built-in stylesheet 'chrome://global/skin/scrollbars.css': file /home/worker/workspace/build/src/layout/style/nsLayoutStylesheetCache.cpp, line 776
[Child 8827] ###!!! ABORT: LoadSheetSync failed with error 80520015 loading built-in stylesheet 'chrome://global/skin/scrollbars.css': file /home/worker/workspace/build/src/layout/style/nsLayoutStylesheetCache.cpp, line 776
[Parent 23874] WARNING: pipe error (127): Connection reset by peer: file /home/worker/workspace/build/src/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 353

[spoji]

Another crash report on Firefox 56 can be found here : https://bugzilla.mozilla.org/show_bug.cgi?id=1389447