Implement DeviceLight

LayoutTests/fast/dom/DeviceLight/script-tests/add-listener-from-callback.js

Index: LayoutTests/fast/dom/DeviceLight/script-tests/add-listener-from-callback.js
diff --git a/LayoutTests/fast/dom/DeviceLight/script-tests/add-listener-from-callback.js b/LayoutTests/fast/dom/DeviceLight/script-tests/add-listener-from-callback.js
new file mode 100644
index 0000000000000000000000000000000000000000..1d180ea2d68f7771e089287d31c3b138ccc461d0
--- /dev/null
+++ b/LayoutTests/fast/dom/DeviceLight/script-tests/add-listener-from-callback.js
@@ -0,0 +1,23 @@
+description('Tests that adding a new devicelight event listener from a callback works as expected.');
+
+var mockLight = 10;
+
+if (window.testRunner) {
+    testRunner.setMockDeviceLight(mockLight);
+    debug('TEST MODE enabled');
+} else
+    debug('This test can not be run without the TestRunner');
+
+var deviceLightEvent;
+function checkLight(event) {
+    deviceLightEvent = event;
+    shouldBe('deviceLightEvent.value', 'mockLight');
+}
+
+function listener(event) {
+    checkLight(event);
+    finishJSTest();
+}
+
+window.addEventListener('devicelight', listener);
+window.jsTestIsAsync = true;