Issue 5347 - Do not show composer menu item on Firefox for Android

lib/filterComposer.js

Index: lib/filterComposer.js
===================================================================
--- a/lib/filterComposer.js
+++ b/lib/filterComposer.js
@@ -175,18 +175,23 @@
 };
 
 function updateContextMenu(page, filter)
 {
   page.contextMenus.remove(contextMenuItem);
 
   if (typeof filter == "undefined")
     filter = checkWhitelisted(page);
-  if (!filter && Prefs.shouldShowBlockElementMenu && readyPages.has(page))
+  if (!filter && Prefs.shouldShowBlockElementMenu && readyPages.has(page) &&
+      // Firefox for Android does not support the windows API, which is
+      // required for the composer to work.

[Wladimir Palant, 2017/08/17 12:22:49]

Not really, we could fall back to creating a new tab - something that makes more
sense on Android anyway.

[Manish Jethani, 2017/08/17 13:25:19]

Do you think it makes sense to make the composer work using tabs? 

Maybe the answer is different for phone and tablet.

Anyway, the composer opens a dialog, I'm not sure it would be a good user
experience to use a tab instead on mobile.

[Sebastian Noack, 2017/08/18 09:23:01]

Also, the user experience when selecting elements isn't great without a mouse,
since elements to be blocked are highlighted on hover so that you know what
would be blocked before you click. This obviously doesn't work on touch devices.
IMO, there is no point to make the composer work there.

[Wladimir Palant, 2017/08/18 20:52:32]

Ok, fine with me.

[Sebastian Noack, 2017/08/23 12:00:35]

Perhaps we should rather check for `info.application != "fennec"` here, since we
seem to agree that the composer doesn't make much sense on mobile, regardless of
the lack of support of the windows API.

[Manish Jethani, 2017/08/24 10:34:59]

Done.

+      "windows" in chrome)
+  {
     page.contextMenus.create(contextMenuItem);
+  }
 }
 
 FilterNotifier.on("page.WhitelistingStateRevalidate", updateContextMenu);
 
 Prefs.on("shouldShowBlockElementMenu", () =>
 {
   ext.pages.query({}, pages =>
   {