Get rid of tab.run_js_blocking

We had some trouble with it, and it's not actually needed.

qutebrowser/browser/browsertab.py

@@ -698,14 +698,6 @@ class AbstractTab(QWidget):
         """
         raise NotImplementedError
 
-    def run_js_blocking(self, code):
-        """Run javascript and block.
-
-        This returns the result to the caller. Its use should be avoided when
-        possible as it runs a local event loop for QtWebEngine.
-        """
-        raise NotImplementedError
-
     def shutdown(self):
         raise NotImplementedError
 

qutebrowser/browser/webengine/webenginetab.py

@@ -448,23 +448,6 @@ class WebEngineTab(browsertab.AbstractTab):
             else:
                 self._widget.page().runJavaScript(code, callback)
 
-    def run_js_blocking(self, code):
-        unset = object()
-        loop = qtutils.EventLoop()
-        js_ret = unset
-
-        def js_cb(val):
-            """Handle return value from JS and stop blocking."""
-            nonlocal js_ret
-            js_ret = val
-            loop.quit()
-
-        self.run_js_async(code, js_cb)
-        loop.exec_()  # blocks until loop.quit() in js_cb
-        assert js_ret is not unset
-
-        return js_ret
-
     def shutdown(self):
         log.stub()
 

qutebrowser/browser/webkit/webkittab.py

@@ -606,13 +606,10 @@ class WebKitTab(browsertab.AbstractTab):
             callback(frame.toHtml())
 
     def run_js_async(self, code, callback=None):
-        result = self.run_js_blocking(code)
+        result = self._widget.page().mainFrame().evaluateJavaScript(code)
         if callback is not None:
             callback(result)
 
-    def run_js_blocking(self, code):
-        return self._widget.page().mainFrame().evaluateJavaScript(code)
-
     def icon(self):
         return self._widget.icon()
 

tests/unit/browser/test_tab.py

@@ -121,11 +121,3 @@ def test_tab(qtbot, view, config_stub, tab_registry, mode_manager):
 
     tab_w.show()
     qtbot.waitForWindowShown(tab_w)
-
-
-class TestJs:
-
-    @pytest.mark.parametrize('inp, expected', [('1+1', 2),
-                                               ('undefined', None)])
-    def test_blocking(self, tab, inp, expected):
-        assert tab.run_js_blocking(inp) == expected