Add AbstractTab.backend attribute

qutebrowser/browser/tab.py

@@ -32,6 +32,9 @@ from qutebrowser.utils import utils, objreg, usertypes
 tab_id_gen = itertools.count(0)
 
 
+Backend = usertypes.enum('Backend', ['QtWebKit', 'QtWebEngine'])
+
+
 class WebTabError(Exception):
 
     """Base class for various errors."""
@@ -416,6 +419,7 @@ class AbstractTab(QWidget):
         self._layout = None
         self._widget = None
         self.keep_icon = False  # FIXME:refactor get rid of this?
+        self.backend = None
 
     def _set_widget(self, widget):
         self._layout = WrapperLayout(widget, self)

qutebrowser/browser/webengine/webenginetab.py

@@ -107,6 +107,7 @@ class WebEngineViewTab(tab.AbstractTab):
         self.search = WebEngineSearch(parent=self)
         self._set_widget(widget)
         self._connect_signals()
+        self.backend = tab.Backend.QtWebEngine
 
     def openurl(self, url):
         self._widget.load(url)

qutebrowser/browser/webkit/webkittab.py

@@ -447,6 +447,7 @@ class WebViewTab(tab.AbstractTab):
         self._set_widget(widget)
         self._connect_signals()
         self.zoom._set_default_zoom()
+        self.backend = tab.Backend.QtWebKit
 
     def openurl(self, url):
         self._widget.openurl(url)