Add the basic code skeleton for system info event router

chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js

Index: chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
diff --git a/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js b/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
index 787ca408abbe912b1aefdc209792a16125c5fe7b..32136973dfccdd80e76abd6e304b1e583f18ca61 100644
--- a/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
+++ b/chrome/test/data/extensions/api_test/systeminfo/storage/test_storage_api.js
@@ -7,14 +7,35 @@
 chrome.systemInfo = chrome.experimental.systemInfo;
 
 chrome.test.runTests([
-  function testGet() {
-    chrome.systemInfo.storage.get(chrome.test.callbackPass(function(info) {
-      chrome.test.assertTrue(info.units.length == 1);
-      var unit = info.units[0];
-      chrome.test.assertTrue(unit.id == "0xbeaf");
-      chrome.test.assertTrue(unit.type == "unknown");
-      chrome.test.assertTrue(unit.capacity == 4098);
-      chrome.test.assertTrue(unit.availableCapacity == 1024);
-    }));
-  }
+function testStorageGet() {
+  chrome.systemInfo.storage.get(chrome.test.callbackPass(function(info) {
+    chrome.test.assertTrue(info.units.length == 1);
+    var unit = info.units[0];
+    chrome.test.assertTrue(unit.id == "0xbeaf");
+    chrome.test.assertTrue(unit.type == "unknown");
+    chrome.test.assertTrue(unit.capacity == 4098);
+    chrome.test.assertTrue(unit.availableCapacity == 1024);
+  }));
+}
 ]);
+
+function testChangedEvent() {
+  var numOfChangedEvent = 0;
+  var base = 10000;
+  var step = 10;
+  var doneChangedEvent = chrome.test.listenForever(
+    chrome.systemInfo.storage.onAvailableCapacityChanged,
+    function listener(changedInfo) {
+      chrome.test.assertTrue(changedInfo.id == "/dev/sda1");
+      chrome.test.assertTrue(
+        changedInfo.availableCapacity == (base - step*numOfChangedEvent));
+      if (++ numOfChangedEvent > 5)
+        doneChangedEvent();
+    });
+}
+
+function onMessageReply() {
+  chrome.test.runTests([testChangedEvent]);
+}
+
+chrome.test.sendMessage("ready", onMessageReply);