Bug 1587804 - Add an Enterprise Policy that allows to set the default search engine used in Private Browsing mode. r=mkaply

Differential Revision: https://phabricator.services.mozilla.com/D49268

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

browser/components/enterprisepolicies/Policies.jsm

@@ -1311,6 +1311,40 @@ var Policies = {
             }
           );
         }
+        if (param.DefaultPrivate) {
+          await runOncePerModification(
+            "setDefaultPrivateSearchEngine",
+            param.DefaultPrivate,
+            async () => {
+              let defaultPrivateEngine;
+              try {
+                defaultPrivateEngine = Services.search.getEngineByName(
+                  param.DefaultPrivate
+                );
+                if (!defaultPrivateEngine) {
+                  throw new Error("No engine by that name could be found");
+                }
+              } catch (ex) {
+                log.error(
+                  `Search engine lookup failed when attempting to set ` +
+                    `the default private engine. Requested engine was ` +
+                    `"${param.DefaultPrivate}".`,
+                  ex
+                );
+              }
+              if (defaultPrivateEngine) {
+                try {
+                  await Services.search.setDefaultPrivate(defaultPrivateEngine);
+                } catch (ex) {
+                  log.error(
+                    "Unable to set the default private search engine",
+                    ex
+                  );
+                }
+              }
+            }
+          );
+        }
       });
     },
   },

browser/components/enterprisepolicies/schemas/policies-schema.json

@@ -952,6 +952,9 @@
         "Default": {
           "type": "string"
         },
+        "DefaultPrivate": {
+          "type": "string"
+        },
         "PreventInstalls": {
           "type": "boolean"
         },

browser/components/enterprisepolicies/tests/browser/browser_policy_search_engine.js

@@ -12,6 +12,9 @@ registerCleanupFunction(() => {
   Services.prefs.clearUserPref(
     "browser.policies.runonce.setDefaultSearchEngine"
   );
+  Services.prefs.clearUserPref(
+    "browser.policies.runonce.setDefaultPrivateSearchEngine"
+  );
   Services.prefs.clearUserPref(
     "browser.policies.runOncePerModification.addSearchEngines"
   );
@@ -111,6 +114,49 @@ add_task(async function test_install_and_set_default() {
   EnterprisePolicyTesting.resetRunOnceState();
 });
 
+add_task(async function test_install_and_set_default_private() {
+  // Make sure we are starting in an expected state to avoid false positive
+  // test results.
+  isnot(
+    (await Services.search.getDefaultPrivate()).name,
+    "MozSearch",
+    "Default search engine should not be MozSearch when test starts"
+  );
+  is(
+    Services.search.getEngineByName("Foo"),
+    null,
+    'Engine "Foo" should not be present when test starts'
+  );
+
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Add: [
+          {
+            Name: "MozSearch",
+            URLTemplate: "http://example.com/?q={searchTerms}",
+          },
+        ],
+        DefaultPrivate: "MozSearch",
+      },
+    },
+  });
+  // Get in line, because the Search policy callbacks are async.
+  await TestUtils.waitForTick();
+
+  // If this passes, it means that the new search engine was properly installed
+  // *and* was properly set as the default.
+  is(
+    (await Services.search.getDefaultPrivate()).name,
+    "MozSearch",
+    "Specified search engine should be the default private engine"
+  );
+
+  // Clean up
+  await Services.search.removeEngine(await Services.search.getDefaultPrivate());
+  EnterprisePolicyTesting.resetRunOnceState();
+});
+
 // Same as the last test, but with "PreventInstalls" set to true to make sure
 // it does not prevent search engines from being installed properly
 add_task(async function test_install_and_set_default_prevent_installs() {