Revert "Inject JS into the profile"

This reverts commit acfb3aa26f.

The related code doesn't really belong in webenginesettings.py after all, and
for some reason I don't understand right now this breaks tests in
javascript.feature because window._qutebrowser is undefined when running them.

qutebrowser/browser/webengine/webenginesettings.py

@@ -193,24 +193,6 @@ def _set_http_headers(profile):
         profile.setHttpAcceptLanguage(accept_language)
 
 
-def _init_js(profile):
-    """Initialize QtWebEngine JavaScript on the given profile."""
-    js_code = '\n'.join([
-        '"use strict";',
-        'window._qutebrowser = {};',
-        utils.read_file('javascript/scroll.js'),
-        utils.read_file('javascript/webelem.js'),
-    ])
-
-    script = QWebEngineScript()
-    script.setInjectionPoint(QWebEngineScript.DocumentCreation)
-    script.setSourceCode(js_code)
-    script.setWorldId(QWebEngineScript.ApplicationWorld)
-    # FIXME:qtwebengine What about runsOnSubFrames?
-
-    profile.scripts().insert(script)
-
-
 def _update_settings(option):
     """Update global settings when qwebsettings changed."""
     websettings.update_mappings(MAPPINGS, option)
@@ -233,13 +215,11 @@ def _init_profiles():
         os.path.join(standarddir.data(), 'webengine'))
     _init_stylesheet(default_profile)
     _set_http_headers(default_profile)
-    _init_js(default_profile)
 
     private_profile = QWebEngineProfile()
     assert private_profile.isOffTheRecord()
     _init_stylesheet(private_profile)
     _set_http_headers(private_profile)
-    _init_js(private_profile)
 
     if qtutils.version_check('5.8'):
         default_profile.setSpellCheckEnabled(True)

qutebrowser/browser/webengine/webenginetab.py

@@ -526,9 +526,27 @@ class WebEngineTab(browsertab.AbstractTab):
         self._set_widget(widget)
         self._connect_signals()
         self.backend = usertypes.Backend.QtWebEngine
+        self._init_js()
         self._child_event_filter = None
         self._saved_zoom = None
 
+    def _init_js(self):
+        js_code = '\n'.join([
+            '"use strict";',
+            'window._qutebrowser = {};',
+            utils.read_file('javascript/scroll.js'),
+            utils.read_file('javascript/webelem.js'),
+        ])
+        script = QWebEngineScript()
+        script.setInjectionPoint(QWebEngineScript.DocumentCreation)
+        script.setSourceCode(js_code)
+
+        page = self._widget.page()
+        script.setWorldId(QWebEngineScript.ApplicationWorld)
+
+        # FIXME:qtwebengine  what about runsOnSubFrames?
+        page.scripts().insert(script)
+
     def _install_event_filter(self):
         self._widget.focusProxy().installEventFilter(self._mouse_event_filter)
         self._child_event_filter = mouse.ChildEventFilter(