Remove Battery Status API support code from Blink

LayoutTests/batterystatus/script-tests/add-listener-from-callback.js

-description('Tests that adding a new event listener from a callback works as expected.');
-
-var charging = false;
-var chargingTime = Number.POSITIVE_INFINITY;
-var dischargingTime = 6000;
-var level = 0.7;
-
-var battery = navigator.webkitBattery;
-
-function checkBatteryStatus() {
-    shouldBe("battery.charging", "false");
-    shouldBe("battery.chargingTime", "Infinity");
-    shouldBe("battery.dischargingTime", "6000");
-    shouldBe("battery.level", "0.7");
-}
-
-var firstListenerEvents = 0;
-function firstListener() {
-    checkBatteryStatus();
-    if (++firstListenerEvents == 1) {
-        battery.addEventListener('chargingchange', secondListener);
-        internals.setBatteryStatus(document, 'chargingchange', charging, chargingTime, dischargingTime, level);
-    }
-    else if (firstListenerEvents > 2)
-        testFailed('Too many events for first listener.');
-    maybeFinishTest();
-}
-
-var secondListenerEvents = 0;
-function secondListener() {
-    checkBatteryStatus();
-    if (++secondListenerEvents > 1)
-        testFailed('Too many events for second listener.');
-    maybeFinishTest();
-}
-
-function maybeFinishTest() {
-    if (firstListenerEvents == 2 && secondListenerEvents == 1)
-        finishJSTest();
-}
-
-battery.addEventListener('chargingchange', firstListener);
-internals.setBatteryStatus(document, 'chargingchange', charging, chargingTime, dischargingTime, level);
-window.jsTestIsAsync = true;