Bug 1827963 - Enable the download button in pdf.js only on nightly in GeckoView r=geckoview-reviewers,amejiamarmol

Differential Revision: https://phabricator.services.mozilla.com/D175389

mobile/android/app/geckoview-prefs.js

@@ -95,3 +95,6 @@ pref("extensions.formautofill.loglevel", "Warn");
 pref("pdfjs.handleOctetStream", true);
 pref("browser.download.open_pdf_attachments_inline", true);
 pref("pdfjs.annotationEditorMode", -1);
+#ifdef NIGHTLY_BUILD
+  pref("pdfjs.enableFloatingToolbar", true);
+#endif

toolkit/components/pdfjs/test/test_pdf_file_in_iframe.html

@@ -18,6 +18,7 @@
             await SpecialPowers.pushPrefEnv({
               "set": [
                 ["pdfjs.disabled", false],
+                ["pdfjs.enableFloatingToolbar", false],
               ],
             });