Refine page media type availability

ext/src/lib/utils.ts

@@ -35,20 +35,49 @@ export function stringify (
 export function getMediaTypesForPageUrl (
         pageUrl: string): ReceiverSelectorMediaType {
 
-    let availableMediaTypes =
-            ReceiverSelectorMediaType.App
-          | ReceiverSelectorMediaType.Tab
-          | ReceiverSelectorMediaType.Screen
-          | ReceiverSelectorMediaType.File;
+    const url = new URL(pageUrl);
+    let availableMediaTypes = ReceiverSelectorMediaType.File;
 
     /**
-     * Remove "Screen" option when on an insecure origin as
-     * MediaDevices.getDisplayMedia will not exist (and legacy
-     * MediaDevices.getUserMedia mediaSource constraint will
-     * fail).
+     * Content scripts are prohibited from running on some
+     * Mozilla domains.
      */
-    if (!pageUrl.startsWith("https://")) {
-        availableMediaTypes &= ~ReceiverSelectorMediaType.Screen;
+    const blockedHosts = [
+        "accounts-static.cdn.mozilla.net"
+      , "accounts.firefox.com"
+      , "addons.cdn.mozilla.net"
+      , "addons.mozilla.org"
+      , "api.accounts.firefox.com"
+      , "content.cdn.mozilla.net"
+      , "content.cdn.mozilla.net"
+      , "discovery.addons.mozilla.org"
+      , "input.mozilla.org"
+      , "install.mozilla.org"
+      , "oauth.accounts.firefox.com"
+      , "profile.accounts.firefox.com"
+      , "support.mozilla.org"
+      , "sync.services.mozilla.com"
+      , "testpilot.firefox.com"
+    ];
+
+    if (blockedHosts.includes(url.host)) {
+        return availableMediaTypes;
+    }
+
+    // Only meant to run on normal web pages
+    if (url.protocol === "http:" || url.protocol === "https:") {
+        availableMediaTypes |= (
+                ReceiverSelectorMediaType.App
+              | ReceiverSelectorMediaType.Tab);
+    }
+
+    /**
+     * When on an insecure origin, MediaDevices.getDisplayMedia
+     * will not exist (and legacy MediaDevices.getUserMedia
+     * mediaSource constraint will fail).
+     */
+    if (url.protocol === "https:") {
+        availableMediaTypes |= ReceiverSelectorMediaType.Screen;
     }
 
     return availableMediaTypes;