Fix initial keyboard focus with QtWebEngine

Fixes #2321.

qutebrowser/misc/miscwidgets.py

@@ -19,12 +19,14 @@
 
 """Misc. widgets used at different places."""
 
+import operator
+
 from PyQt5.QtCore import pyqtSlot, pyqtSignal, Qt, QSize, QTimer
 from PyQt5.QtWidgets import (QLineEdit, QWidget, QHBoxLayout, QLabel,
                              QStyleOption, QStyle, QLayout, QApplication)
 from PyQt5.QtGui import QValidator, QPainter
 
-from qutebrowser.utils import utils, objreg
+from qutebrowser.utils import utils, objreg, qtutils, log
 from qutebrowser.misc import cmdhistory
 
 
@@ -260,6 +262,15 @@ class WrapperLayout(QLayout):
         self._widget = widget
         container.setFocusProxy(widget)
         widget.setParent(container)
+        if (qtutils.version_check('5.8.0', op=operator.eq) and
+                container.window() and
+                container.window().windowHandle() and
+                not container.window().windowHandle().isActive()):
+            log.misc.debug("Calling QApplication::sync...")
+            # WORKAROUND for:
+            # https://bugreports.qt.io/browse/QTBUG-56652
+            # https://codereview.qt-project.org/#/c/176113/5//ALL,unified
+            QApplication.sync()
 
     def unwrap(self):
         self._widget.setParent(None)

tests/end2end/fixtures/quteprocess.py

@@ -209,15 +209,22 @@ class QuteProc(testprocess.Process):
             "load status for <qutebrowser.browser.* tab_id=0 "
             "url='about:blank'>: LoadStatus.success")
         start_okay_messages_focus = [
-            # QtWebKit
+            ## QtWebKit
             "Focus object changed: "
             "<qutebrowser.browser.* tab_id=0 url='about:blank'>",
-            # QtWebEngine
+            # when calling QApplication::sync
+            "Focus object changed: "
+            "<qutebrowser.browser.webkit.webview.WebView tab_id=0 url=''>",
+
+            ## QtWebEngine
             "Focus object changed: "
             "<PyQt5.QtWidgets.QOpenGLWidget object at *>",
-            # QtWebEngine with Qt >= 5.8
+            # with Qt >= 5.8
             "Focus object changed: "
             "<PyQt5.QtGui.QWindow object at *>",
+            # when calling QApplication::sync
+            "Focus object changed: "
+            "<PyQt5.QtWidgets.QWidget object at *>",
         ]
 
         if (log_line.category == 'ipc' and