Bug 1630228 - Enable F12 for all users with selfxss pref > 0 r=Harald,nchevobbe

Depends on D71036

Differential Revision: https://phabricator.services.mozilla.com/D71037

devtools/startup/DevToolsStartup.jsm

@@ -28,6 +28,7 @@ const kDebuggerPrefs = [
 ];
 
 const DEVTOOLS_ENABLED_PREF = "devtools.enabled";
+const DEVTOOLS_F12_DISABLED_PREF = "devtools.experiment.f12.shortcut_disabled";
 
 const DEVTOOLS_POLICY_DISABLED_PREF = "devtools.policy.disabled";
 
@@ -364,6 +365,13 @@ DevToolsStartup.prototype = {
       // is over).
       Services.prefs.setBoolPref(DEVTOOLS_ENABLED_PREF, true);
 
+      // The F12 shortcut might be disabled to avoid accidental usage.
+      // Users who are already considered as devtools users should not be
+      // impacted.
+      if (this.isDevToolsUser()) {
+        Services.prefs.setBoolPref(DEVTOOLS_F12_DISABLED_PREF, false);
+      }
+
       // Store devtoolsFlag to check it later in onWindowReady.
       this.devtoolsFlag = flags.devtools;