keyboard doesn't display in webapps after some time

wondering if could be related to https://bugs.launchpad.net/ubuntu-keyboard/+bug/1306656

It could be due to popup windows somehow stealing the focus of the main webview. I noticed OSK issues while debugging Gmail account switching, which triggers popup redirections.

I am able to reliably reproduce with the following simple steps:

 1) launch the twitter webapp
      - log in
      - press the button to write a new tweet
      - tap in the text field to summon the OSK
      - input some characters
      - dismiss the screen by either posting the tweet or canceling and discarding it
 2) back at the tweet list, click on an external link in any tweet
      - this opens the link in the browser application
 3) swipe from the right edge to go back to the twitter webapp
      - press the button to write a new tweet
      - tap in the text field to summon the OSK

Expected result: the OSK shows up
Current result: no OSK

I'm now able to actually reproduce with even fewer steps, just opening twitter and visiting an external link, then swiping right is enough to trigger it. The keyboard doesn't even need to have been shown beforehand.

It seems oxide is sending visibility change requests correctly when the focused node changes, however the keyboard plugin never receives them, so I'm now taking a look at the maliit framework to try and work out what happens in between to cause the request to go missing.

Interestingly if the maliit-server is restarted after the bug has been triggered the keyboard will start displaying in the twitter webapp again.

The workaround for this seems to cause a crash when running the unit tests if the window loses focus. I guess this will probably happen in the browser as well:

#0 0x00007fffc85eed25 in oxide::qt::RenderWidgetHostView::FocusedNodeChanged (this=0x10dedc0, is_editable_node=<optimised out>)
    at ../../../../qt/core/browser/oxide_qt_render_widget_host_view.cc:823
#1 0x00007fffca8b8cba in content::RenderViewHostImpl::OnFocusedNodeChanged (this=this@entry=0x2692550, is_editable_node=false)
    at ../../../../third_party/chromium/src/content/browser/renderer_host/render_view_host_impl.cc:1307
#2 0x00007fffca8c35a0 in DispatchToMethod<content::RenderViewHostImpl, void (content::RenderViewHostImpl::*)(bool), bool> (arg=..., method=
    (void (content::RenderViewHostImpl::*)(content::RenderViewHostImpl * const, bool)) 0x7fffca8b8c90 <content::RenderViewHostImpl::OnFocusedNodeChanged(bool)>, obj=0x2692550)
    at ../../../../third_party/chromium/src/base/tuple.h:548
#3 Dispatch<content::RenderViewHostImpl, content::RenderViewHostImpl, void, void (content::RenderViewHostImpl::*)(bool)> (sender=<optimised out>, parameter=0x0, func=
    (void (content::RenderViewHostImpl::*)(content::RenderViewHostImpl * const, bool)) 0x7fffca8b8c90 <content::RenderViewHostImpl::OnFocusedNodeChanged(bool)>, obj=0x2692550, msg=
    0x7fff8c06cc68) at ../../../../third_party/chromium/src/content/common/view_messages.h:1170
#4 content::RenderViewHostImpl::OnMessageReceived (this=0x2692550, msg=...) at ../../../../third_party/chromium/src/content/browser/renderer_host/render_view_host_impl.cc:998
#5 0x00007fffca8b17a1 in content::RenderProcessHostImpl::OnMessageReceived (this=0x2691e30, msg=...)
    at ../../../../third_party/chromium/src/content/browser/renderer_host/render_process_host_impl.cc:1416
#6 0x00007fffc8c7c9e2 in IPC::ChannelProxy::Context::OnDispatchMessage (this=0x10e19a0, message=...) at ../../../../third_party/chromium/src/ipc/ipc_channel_proxy.cc:273
#7 0x00007fffc867dedb in Run (this=0x7fffffffabb8) at ../../../../third_party/chromium/src/base/callback.h:401
#8 base::MessageLoop::RunTask (this=this@entry=0xda2890, pending_task=...) at ../../../../third_party/chromium/src/base/message_loop/message_loop.cc:450
#9 0x00007fffc867e921 in base::MessageLoop::DeferOrRunPendingTask (this=this@entry=0xda2890, pending_task=...)
    at ../../../../third_party/chromium/src/base/message_loop/message_loop.cc:462
#10 0x00007fffc8682185 in base::MessageLoop::DoWork (this=0xda2890) at ../../../../third_party/chromium/src/base/message_loop/message_loop.cc:576
#11 0x00007fffc85ee66a in oxide::qt::MessagePump::customEvent (this=0xd9e3f0, event=<optimised out>) at ../../../../qt/core/browser/oxide_qt_message_pump.cc:60
#12 0x00007ffff79c42ad in QObject::event (this=0xd9e3f0, e=<optimised out>) at kernel/qobject.cpp:1169
#13 0x00007ffff799befd in QCoreApplication::notify (this=<optimised out>, receiver=<optimised out>, event=<optimised out>) at kernel/qcoreapplication.cpp:943
#14 0x00007ffff799bc2d in QCoreApplication::notifyInternal (this=0x7fffffffd800, receiver=0xd9e3f0, event=event@entry=0x10f55e0) at kernel/qcoreapplication.cpp:881
#15 0x00007ffff799de07 in sendEve...

Backed this out for now. Michael, would you mind taking a look at that crash please?