merge from upstream (#4)

* webhelper: Initial port to webkit2gtk

* webhelper: Initialize webkit favicon database

This fixes missing favicons in webhelper.

* webhelper: Fix ctrl+scroll zooming in gtk3

* webhelper: Port context menu to WebKitContextMenu

* webhelper: Use the right type for GSimpleAction

* webhelper: Port link hovering functionality to webkit2gtk

* webhelper: Fix constness of a variable

cairo_image_surface_get_width() and friends expects a non-const
cairo_surface_t.

* webhelper: Add missing G_CALLBACK() casts

* webhelper: Avoid a deprecation

* webhelper: Make gtk3-only

webkit2gtk-4.0 doesn't exist for gtk2.

* webhelper: Remove pre-GTK3 compatibility checks

Now we depend on the GTK3-only WebKit2Gtk, drop code for compatibility
GTK2.

* webhelper: Don't use deprecated GtkStock

* webhelper: Port inspector signal handlers to webkit2gtk

* webhelper: Fix flip-panes action

* webhelper: Remove custom docking position support

This is supported by WebKit2Gtk itself, and not controllable by the
application, so just drop the useless code.

* webhelper: Fix loading progress display

* webhelper: Fix state of the Full-content zoom menu item

The initial state was incorrect, and although the state was properly
updated upon toggling, WebKit doesn't actually use the value itself but
tracks toggle operations on its own, so it would not fix itself for
subsequent changes either.

* webhelper: Fix leaking GActions

GActions are not GInitiallyUnowned, so we have to manually unref them.

* webhelper: Fix internal browser-auto-reload menu item state

This doesn't change anything though, as currently WebKit doesn't
actually use that value, and neither do we.

* webhelper: Improve style

* Reorder calls to be more consistent when it doesn't affect behavior;
* Remove unnecessary call setting a default value;
* Better manage line length.

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Co-authored-by: Chow Loong Jin <hyperair@debian.org>
Co-authored-by: Colomban Wendling <ban@herbesfolles.org>

Author: 3 people