Add content.javascript.legacy_touch_events setting

Closes #7814

5 files changed, 53 insertions, 0 deletions

diff --git a/doc/changelog.asciidoc b/doc/changelog.asciidoc
index 36c18d65c..e3fe5784f 100644
--- a/doc/changelog.asciidoc
+++ b/doc/changelog.asciidoc
@@ -31,6 +31,8 @@ Added
 - New `smart-simple` value for `colors.webpage.darkmode.policy.images`, which on
   QtWebEngine 6.6+ uses a simpler classification algorithm to decide whether to
   invert images.
+- New `content.javascript.legacy_touch_events` setting, with those now being
+  disabled by default, following a Chromium change.
 
 Changed
 ~~~~~~~
diff --git a/doc/help/settings.asciidoc b/doc/help/settings.asciidoc
index b6f61ab03..9ef0a014d 100644
--- a/doc/help/settings.asciidoc
+++ b/doc/help/settings.asciidoc
@@ -171,6 +171,7 @@
 |<<content.javascript.can_open_tabs_automatically,content.javascript.can_open_tabs_automatically>>|Allow JavaScript to open new tabs without user interaction.
 |<<content.javascript.clipboard,content.javascript.clipboard>>|Allow JavaScript to read from or write to the clipboard.
 |<<content.javascript.enabled,content.javascript.enabled>>|Enable JavaScript.
+|<<content.javascript.legacy_touch_events,content.javascript.legacy_touch_events>>|Enables the legacy touch event feature.
 |<<content.javascript.log,content.javascript.log>>|Log levels to use for JavaScript console logging messages.
 |<<content.javascript.log_message.excludes,content.javascript.log_message.excludes>>|Javascript messages to *not* show in the UI, despite a corresponding `content.javascript.log_message.levels` setting.
 |<<content.javascript.log_message.levels,content.javascript.log_message.levels>>|Javascript message sources/levels to show in the qutebrowser UI.
@@ -2365,6 +2366,27 @@ Type: <<types,Bool>>
 
 Default: +pass:[true]+
 
+[[content.javascript.legacy_touch_events]]
+=== content.javascript.legacy_touch_events
+Enables the legacy touch event feature.
+This affects JS APIs such as:
+- ontouch* members on window, document, Element - document.createTouch, document.createTouchList - document.createEvent("TouchEvent")
+Newer Chromium versions have those disabled by default: https://bugs.chromium.org/p/chromium/issues/detail?id=392584 https://groups.google.com/a/chromium.org/g/blink-dev/c/KV6kqDJpYiE
+
+This setting requires a restart.
+
+This setting is only available with the QtWebEngine backend.
+
+Type: <<types,String>>
+
+Valid values:
+
+ * +always+: Legacy touch events are always enabled. This might cause some websites to assume a mobile device.
+ * +auto+: Legacy touch events are only enabled if a touch screen was detected on startup.
+ * +never+: Legacy touch events are always disabled.
+
+Default: +pass:[never]+
+
 [[content.javascript.log]]
 === content.javascript.log
 Log levels to use for JavaScript console logging messages.
diff --git a/qutebrowser/config/configdata.yml b/qutebrowser/config/configdata.yml
index cddac7353..ff45b355d 100644
--- a/qutebrowser/config/configdata.yml
+++ b/qutebrowser/config/configdata.yml
@@ -1031,6 +1031,29 @@ content.javascript.prompt:
   type: Bool
   desc: Show javascript prompts.
 
+content.javascript.legacy_touch_events:
+  type:
+    name: String
+    valid_values:
+      - always: Legacy touch events are always enabled. This might cause some websites to assume a mobile device.
+      - auto: Legacy touch events are only enabled if a touch screen was detected on startup.
+      - never: Legacy touch events are always disabled.
+  default: never
+  backend: QtWebEngine
+  restart: true
+  desc: >-
+    Enables the legacy touch event feature.
+
+    This affects JS APIs such as:
+
+    - ontouch* members on window, document, Element
+    - document.createTouch, document.createTouchList
+    - document.createEvent("TouchEvent")
+
+    Newer Chromium versions have those disabled by default:
+    https://bugs.chromium.org/p/chromium/issues/detail?id=392584
+    https://groups.google.com/a/chromium.org/g/blink-dev/c/KV6kqDJpYiE
+
 content.local_content_can_access_remote_urls:
   default: false
   type: Bool
diff --git a/qutebrowser/config/qtargs.py b/qutebrowser/config/qtargs.py
index 06e260de9..3a648524e 100644
--- a/qutebrowser/config/qtargs.py
+++ b/qutebrowser/config/qtargs.py
@@ -309,6 +309,11 @@ _WEBENGINE_SETTINGS: Dict[str, Dict[Any, Optional[_SettingValueType]]] = {
             '--force-webrtc-ip-handling-policy='
             'disable_non_proxied_udp',
     },
+    'content.javascript.legacy_touch_events': {
+        'always': '--touch-events=enabled',
+        'auto': '--touch-events=auto',
+        'never': '--touch-events=disabled',
+    },
     'qt.chromium.process_model': {
         'process-per-site-instance': None,
         'process-per-site': '--process-per-site',
diff --git a/tests/unit/config/test_qtargs.py b/tests/unit/config/test_qtargs.py
index 2414d4ba9..d8980bb53 100644
--- a/tests/unit/config/test_qtargs.py
+++ b/tests/unit/config/test_qtargs.py
@@ -77,6 +77,7 @@ class TestQtArgs:
     ])
     def test_qt_args(self, monkeypatch, config_stub, args, expected, parser):
         """Test commandline with no Qt arguments given."""
+        expected.append("--touch-events=disabled")  # passed unconditionally
         parsed = parser.parse_args(args)
         assert qtargs.qt_args(parsed) == expected