Add sample extensions that use the text-to-speech (TTS) API.

chrome/common/extensions/docs/examples/extensions/talking_alarm_clock/background.js

+var a1Timer = null;
+var a2Timer = null;
+var port = null;
+var iconFlashTimer = null;
+
+var HOUR_MS = 1000 * 60 * 60;
+
+// Override from common.js
+window.stopFlashingIcon = function() {
+  window.clearTimeout(iconFlashTimer);
+  chrome.browserAction.setIcon({'path': 'clock-19.png'});
+};
+
+// Override from common.js
+window.flashIcon = function() {
+  var flashes = 10;
+  function flash() {
+    if (flashes == 0) {
+      stopFlashingIcon();
+      return;
+    }
+
+    if (flashes % 2 == 0) {
+      chrome.browserAction.setIcon({'path': 'clock-highlighted-19.png'});
+    } else {
+      chrome.browserAction.setIcon({'path': 'clock-19.png'});
+    }
+    flashes--;
+    iconFlashTimer = window.setTimeout(flash, 500);
+  }
+  flash();
+};
+
+function setTimer(alarmHours, alarmMinutes) {
+  var alarmTime = (alarmHours * 60 + alarmMinutes) * 60 * 1000;
+  var d = new Date();
+  var now = d.getHours() * HOUR_MS +
+            d.getMinutes() * 60 * 1000 +
+            d.getSeconds() * 1000;
+  var delta = (alarmTime - now);
+
+  if (delta >= -5000 && delta < 1000) {
+    ringAlarm(alarmHours, alarmMinutes);
+    if (port) {
+      port.postMessage({'cmd': 'anim'});
+    }
+    return null;
+  }
+
+  if (delta < 0) {
+    delta += HOUR_MS * 24;
+  }
+  if (delta >= 1000) {
+    if (delta > HOUR_MS) {
+      delta = HOUR_MS;
+    }
+    console.log('Timer set for ' + delta + ' ms');
+    return window.setTimeout(resetTimers, delta);
+  }
+
+  return null;
+};
+
+function resetTimers() {
+  if (a1Timer) {
+    window.clearTimeout(a1Timer);
+  }
+
+  try {
+    var a1_on = (localStorage['a1_on'] == 'true');
+    var a1_tt = localStorage['a1_tt'] || DEFAULT_A1_TT;
+    var a1_ampm = localStorage['a1_ampm'] || DEFAULT_A1_AMPM;
+    if (a1_on) {
+      var alarmHoursMinutes = parseTime(a1_tt, a1_ampm);
+      var alarmHours = alarmHoursMinutes[0];
+      var alarmMinutes = alarmHoursMinutes[1];
+      a1Timer = setTimer(alarmHours, alarmMinutes);
+    }
+  } catch (e) {
+    console.log(e);
+  }
+
+  try {
+    var a2_on = (localStorage['a2_on'] == 'true');
+    var a2_tt = localStorage['a2_tt'] || DEFAULT_A2_TT;
+    var a2_ampm = localStorage['a2_ampm'] || DEFAULT_A2_AMPM;
+    if (a2_on) {
+      var alarmHoursMinutes = parseTime(a2_tt, a2_ampm);
+      var alarmHours = alarmHoursMinutes[0];
+      var alarmMinutes = alarmHoursMinutes[1];
+      a2Timer = setTimer(alarmHours, alarmMinutes);
+    }
+  } catch (e) {
+    console.log(e);
+  }
+
+  if (a1_on || a2_on) {
+    chrome.browserAction.setIcon({'path': 'clock-19.png'});
+  } else {
+    chrome.browserAction.setIcon({'path': 'clock-disabled-19.png'});
+  }
+}
+
+function onLocalStorageChange() {
+  resetTimers();
+}
+
+function initBackground() {
+  window.addEventListener('storage', onLocalStorageChange, false);
+
+  chrome.extension.onConnect.addListener(function(popupPort) {
+    port = popupPort;
+    port.onDisconnect.addListener(function() {
+      port = null;
+    });
+  });
+}
+
+initBackground();
+resetTimers();