File history links give an error after a session restore

[Tom Goddard]

After restoring a session, all links in the file history tool are broken (Qt version). The click seems to go to handle_schema() defined in core.ui.gui.py instead of the file history tool link handler which is registered using

fhw.page().acceptNavigationRequest = link_clicked

where fhw is a QWebEngineView (the file history panel widget). The file history works correctly before session restore. Not sure what session restore is doing that breaks it.

Traceback (most recent call last):
File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimerax/core/ui/gui.py", line 785, in handle_schema
run(self.session, "help %s" % qurl.toString(), log=False)
File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimerax/core/commands/run.py", line 21, in run
return command.run(text, log=log)
File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimerax/core/commands/cli.py", line 2194, in run
results.append(ci.function(session, kw_args))
File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimerax/help_viewer/cmd.py", line 30, in help
if ti.bundle_info.name == 'cmd_line':
AttributeError: 'NoneType' object has no attribute 'bundle_info'

[Tom Goddard]

Fixed.

QWebEngineView link dispatching for unrecognized schema's is done globally. The file history links were being dispatched through the help command, and the help command was broken after session restore. I made dispatching of cxcmd links in core/ui/gui.py not use the help command, but instead just run the command.