Create youtube-theater-fix.js, fixes brave/brave-browser#29591 (#118)

* Create youtube-theater-fix.js, fixes brave/brave-browser#29591

adds a scriptlet to mirror the session cookie value in localstorage

* Update youtube-theater-fix.js

* Fix youtube scriptlet, add build output

* Store cookie as a JSON string

* Only set localstorage if cookie exists, else delete localstorage entry

To make sure that they are in sync

---------

Co-authored-by: Shivan Kaul Sahib <shivankaulsahib@gmail.com>

metadata.json

@@ -55,6 +55,14 @@
         },
         "resourcePath": "brave-set-session-storage-item.js"
     },
+    {
+        "name": "brave-youtube-theater-fix",
+        "aliases": [],
+        "kind": {
+            "mime": "application/javascript"
+        },
+        "resourcePath": "brave-youtube-theater-fix.js"
+    },
     {
         "name": "de-amp",
         "aliases": [],

resources/brave-youtube-theater-fix.js

@@ -0,0 +1,30 @@
+(async _ => {
+  if (self.cookieStore === undefined) {
+    // Do nothing on iOS. The problem doesn't exist there, and the
+    // solution wouldn't work anyway
+    return
+  }
+  const storeKey = 'brave::wide'
+  const cookieKey = 'wide'
+  // If we have a localStorage value, set it as a cookie.
+  if (localStorage.getItem(storeKey) !== null) {
+    // The cookie object is stored as a string. Parse it.
+    const cookieObj = JSON.parse(localStorage.getItem(storeKey))
+    await cookieStore.set(cookieObj)
+  }
+
+  // Persist the cookie value to localStorage every second.
+  setInterval(async _ => {
+    try {
+      const wideCookie = await cookieStore.get(cookieKey)
+      // We have to stringify the cookie object to store it in localStorage.
+      if (wideCookie) {
+        localStorage.setItem(storeKey, JSON.stringify(wideCookie))
+      } else {
+        localStorage.removeItem(storeKey)
+      }
+    } catch (e) {
+      // swallow error from no cookie existing
+    }
+  }, 1000)
+})()