Bug 1518663 - If policy extension download fails, try again. r=Felipe

Differential Revision: https://phabricator.services.mozilla.com/D25830

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

browser/components/enterprisepolicies/Policies.jsm

@@ -552,6 +552,7 @@ var Policies = {
                 onDownloadFailed: () => {
                   install.removeListener(listener);
                   log.error(`Download failed - ${location}`);
+                  clearRunOnceModification("extensionsInstall");
                 },
                 onInstallFailed: () => {
                   install.removeListener(listener);
@@ -1151,6 +1152,16 @@ async function runOncePerModification(actionName, policyValue, callback) {
   return callback();
 }
 
+/**
+ * clearRunOnceModification
+ *
+ * Helper function that clears a runOnce policy.
+*/
+function clearRunOnceModification(actionName) {
+  let prefName = `browser.policies.runOncePerModification.${actionName}`;
+  Services.prefs.clearUserPref(prefName);
+}
+
 let gChromeURLSBlocked = false;
 
 // If any about page is blocked, we block the loading of all

browser/components/enterprisepolicies/tests/browser/browser_policy_extensions.js

@@ -92,21 +92,44 @@ add_task(async function test_addon_uninstall() {
   is(addon, null, "Addon should be uninstalled.");
 });
 
+add_task(async function test_addon_download_failure() {
+  // Test that if the download fails, the runOnce pref
+  // is cleared so that the dowbnload will happen again
+
+  let installPromise = wait_for_addon_install();
+  await setupPolicyEngineWithJson({
+    "policies": {
+      "Extensions": {
+        "Install": [
+          `${BASE_URL}/policytest_invalid.xpi`,
+        ],
+      },
+    },
+  });
+
+  await installPromise;
+  is(Services.prefs.prefHasUserValue("browser.policies.runOncePerModification.extensionsInstall"), false, "runOnce pref should be unset");
+});
+
 function wait_for_addon_install() {
-  return new Promise((resolve, reject) => {
-      AddonManager.addInstallListener({
-        onInstallEnded(install, addon) {
-          if (addon.id == addonID) {
-            resolve();
-          }
-        },
-        onDownloadFailed: (install) => {
-          reject();
-        },
-        onInstallFailed: (install) => {
-          reject();
-        },
-      });
+  return new Promise(resolve => {
+    let listener = {
+      onInstallEnded(install, addon) {
+        if (addon.id == addonID) {
+          AddonManager.removeInstallListener(listener);
+          resolve();
+        }
+      },
+      onDownloadFailed() {
+        AddonManager.removeInstallListener(listener);
+        resolve();
+      },
+      onInstallFailed() {
+        AddonManager.removeInstallListener(listener);
+        resolve();
+      },
+    };
+    AddonManager.addInstallListener(listener);
   });
 }