[WebRequest] Remove AddonManagerPermissions leftovers

This was added as part of the WebExtension sec issue CVE-2017-5389.
Since we no longer have this interface, it needed to be removed to
prevent errors in the WebRequest channel callback.

dom/bindings/Bindings.conf

@@ -53,11 +53,6 @@ DOMInterfaces = {
     'concrete': False
 },
 
-'AddonManagerPermissions': {
-    'wrapperCache': False,
-    'concrete': False
-},
-
 'AnimationEffectReadOnly': {
     'concrete': False
 },

toolkit/modules/addons/.eslintrc.js

@@ -8,7 +8,6 @@ module.exports = { // eslint-disable-line no-undef
     "addMessageListener": false,
     "removeEventListener": false,
     "sendAsyncMessage": false,
-    "AddonManagerPermissions": false,
 
     "initialProcessData": true,
   },

toolkit/modules/addons/WebRequest.jsm

@@ -720,11 +720,7 @@ HttpObserverManager = {
         try {
           let result = callback(data);
 
-          if (result && typeof result === "object" && opts.blocking
-              && !AddonManagerPermissions.isHostPermitted(uri.host)
-              && (!loadInfo || !loadInfo.loadingPrincipal
-                  || !loadInfo.loadingPrincipal.URI
-                  || !AddonManagerPermissions.isHostPermitted(loadInfo.loadingPrincipal.URI.host))) {
+          if (result && typeof result === "object" && opts.blocking) {
             handlerResults.push({opts, result});
           }
         } catch (e) {