Bug 1216207 - Modify navigator.hasFeature method to implement new

late-customization feature detection and change the test as well
r=ehsan

dom/base/Navigator.cpp

@@ -1607,9 +1607,10 @@ Navigator::HasFeature(const nsAString& aName, ErrorResult& aRv)
     return nullptr;
   }
 
-  // Hardcoded web-extensions feature which is b2g specific.
+  // Hardcoded extensions features which are b2g specific.
 #ifdef MOZ_B2G
-  if (aName.EqualsLiteral("web-extensions")) {
+  if (aName.EqualsLiteral("web-extensions") ||
+      aName.EqualsLiteral("late-customization")) {
     p->MaybeResolve(true);
     return p.forget();
   }

dom/base/test/test_hasFeature.html

@@ -65,11 +65,19 @@ function testExtensions() {
     return Promise.resolve();
   }
 
-  return navigator.hasFeature("web-extensions").then(function(value) {
+  var builtInFeatures = [
-    is(value, true, "Resolve the Promise with " + value + " for web-extensions");
+    {feature: "web-extensions", value: true},
-  }, function() {
+    {feature: "late-customization", value: true}
-    ok(false, "The Promise should not be rejected");
+  ];
+
+  builtInFeatures.forEach(function(x) {
+    navigator.hasFeature(x.feature).then(function(value) {
+      is(value, x.value, "Resolve the Promise with " + value + " for feature: " + x.feature);
+    }).catch(function(ex) {
+      ok(false, "The Promise should not be rejected");
+    });
   });
+  return Promise.resolve();
 }
 
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