Google Docs accessibility (#1875)

* Add accessibility option for forcing Google Docs HTML-based rendering

* Update settings

* Send a documentStart message at document start

* Add accessibility script for Google Docs

* Set up accessibility

* Update tests

1 files changed, 27 insertions, 0 deletions

diff --git a/ext/js/accessibility/google-docs.js b/ext/js/accessibility/google-docs.js
new file mode 100644
index 00000000..f9ba0f7f
--- /dev/null
+++ b/ext/js/accessibility/google-docs.js
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+(() => {
+    let parent = document.head;
+    if (parent === null) {
+        parent = document.documentElement;
+        if (parent === null) { return; }
+    }
+    const script = document.createElement('script');
+    script.textContent = 'window._docs_force_html_by_ext = true;';
+    parent.appendChild(script);
+})();