Bug 1544890 - Disable addon-abuse-report-xulframe if AbuseReporter.openDialogDisabled is false. r=mstriemer

This patch prevents the addon-abuse-report-xulframe custom element from being defined
when AbuseReporter.openDialogDisabled is false (which is the default on all channels
starting from Firefox >= 73).

This change is also preventing the addon-abuse-report-xulframe custom element from
triggering an assertion failure in PresShell::ScrollContentIntoView, which seems to
be due to marionette calling browser.focus() while the custom element has just
injected the browser element that would contain the abuse report panel subframe.

This single-line patch is enough to prevent the assertion failure and still pass
all the existing tests. The addon-abuse-report-xulframe will be removed completely
as part of Bug 1614653.

Depends on D68805

Differential Revision: https://phabricator.services.mozilla.com/D71005

--HG--
extra : moz-landing-system : lando

toolkit/mozapps/extensions/content/abuse-report-frame.js

@@ -271,7 +271,7 @@
   // If the html about:addons and the abuse report are both enabled, register
   // the custom XUL WebComponent and append it to the XUL stack element
   // (if not registered the element will be just a dummy hidden box)
-  if (ABUSE_REPORT_ENABLED) {
+  if (ABUSE_REPORT_ENABLED && AbuseReporter.openDialogDisabled) {
     customElements.define(
       "addon-abuse-report-xulframe",
       AddonAbuseReportsXULFrame