Scrolling position is not saved with tabs lazy loading

[wedens]

When lazy_restore is enabled, restoring session doesn't restore tabs scrolling positions. With lazy_restore disabled it works as expected.

qutebrowser v1.3.0
Git commit: 12e0edbcd (2018-05-24 08:47:31 +0200)
Backend: QtWebEngine (Chromium 65.0.3325.151)

CPython: 3.6.5
Qt: 5.11.0
PyQt: 5.10.1

sip: 4.19.8
colorama: no
pypeg2: 2.15
jinja2: 2.10
pygments: 2.2.0
yaml: 3.12
cssutils: no
attr: 18.1.0
PyQt5.QtWebEngineWidgets: yes
PyQt5.QtWebKitWidgets: no
pdf.js: 1.9.426 (/usr/share/pdf.js/build/pdf.js)
sqlite: 3.23.1
QtNetwork SSL: OpenSSL 1.1.0h  27 Mar 2018

Style: QFusionStyle
Platform: Linux-4.16.11-1-ARCH-x86_64-with-arch, 64bit
Linux distribution: Arch Linux (arch)
Frozen: False
Imported from /usr/lib/python3.6/site-packages/qutebrowser
Using Python from /bin/python
Qt library executable path: /usr/lib/qt/libexec, data path: /usr/share/qt

Paths:
cache: /home/wedens/.cache/qutebrowser
config: /home/wedens/.config/qutebrowser
data: /home/wedens/.local/share/qutebrowser
runtime: /run/user/1000/qutebrowser
system data: /usr/share/qutebrowser

[toofar]

This is not unsurprising given the implementation. On one hand it may not be worth fixing until how lazy loading is done is revamped (which would be quite a bit of work), on the other hand even when that is done the code would probably have to special case around that lazy implementation so special casing around this implementation may not be so silly. Unless in that case tab.get_page() would return something whos' "signals" connect() methods just saved the functions for when the actual page showed up and then connected them...
In any case, I imagine if we were to bother fixing this the fix would look something like changing to_point() to check if the tab was on qute://back and connecting a lambda, which connected to_point to loadFinished, to tab.urlChanged or something.