Get rid of tab.run_webaction

As mentioned here:
e4b0b7fffd (r70002693)

It makes no sense to add a backend-specific run_webaction method to
AbstractTab - better to just access _widget directly in this one place
instead of adding something backend-speficic to the API.

qutebrowser/browser/commands.py

@@ -1679,7 +1679,10 @@ class CommandDispatcher:
                 action))
 
         for _ in range(count):
-            tab.run_webaction(member)
+            # This whole command is backend-specific anyways, so it makes no
+            # sense to introduce some API for this.
+            # pylint: disable=protected-access
+            tab._widget.triggerPageAction(member)
 
     @cmdutils.register(instance='command-dispatcher', scope='window',
                        maxsplit=0, no_cmd_split=True)

qutebrowser/browser/tab.py

@@ -527,9 +527,6 @@ class AbstractTab(QWidget):
     def icon(self):
         raise NotImplementedError
 
-    def run_webaction(self, action):
-        raise NotImplementedError
-
     def set_html(self, html, base_url):
         raise NotImplementedError
 

qutebrowser/browser/webengine/webenginetab.py

@@ -228,9 +228,6 @@ class WebEngineViewTab(tab.AbstractTab):
     def icon(self):
         return self._widget.icon()
 
-    def run_webaction(self, action):
-        self._widget.triggerPageAction(action)
-
     def set_html(self, html, base_url):
         # FIXME:qtwebengine
         # check this and raise an exception if too big:

qutebrowser/browser/webkit/webkittab.py

@@ -499,7 +499,7 @@ class WebViewTab(tabmod.AbstractTab):
             action = QWebPage.ReloadAndBypassCache
         else:
             action = QWebPage.Reload
-        self.run_webaction(action)
+        self._widget.triggerPageAction(action)
 
     def stop(self):
         self._widget.stop()
@@ -511,9 +511,6 @@ class WebViewTab(tabmod.AbstractTab):
         nam = self._widget.page().networkAccessManager()
         nam.clear_all_ssl_errors()
 
-    def run_webaction(self, action):
-        self._widget.triggerPageAction(action)
-
     def set_html(self, html, base_url):
         self._widget.setHtml(html, base_url)