chrome.bluetoothLowEnergy: Implement the onDescriptorValueChanged event.

chrome/test/data/extensions/api_test/bluetooth_low_energy/descriptor_value_changed/runtest.js

Index: chrome/test/data/extensions/api_test/bluetooth_low_energy/descriptor_value_changed/runtest.js
diff --git a/chrome/test/data/extensions/api_test/bluetooth_low_energy/descriptor_value_changed/runtest.js b/chrome/test/data/extensions/api_test/bluetooth_low_energy/descriptor_value_changed/runtest.js
new file mode 100644
index 0000000000000000000000000000000000000000..c16a4c9534a5d7987e9ec60db1b12dc80b742816
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/bluetooth_low_energy/descriptor_value_changed/runtest.js
@@ -0,0 +1,25 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function testDescriptorValueChanged() {
+  chrome.test.assertEq(2, Object.keys(changedDescs).length);
+
+  chrome.test.assertEq(descId0, changedDescs[descId0].instanceId);
+  chrome.test.assertEq(descId1, changedDescs[descId1].instanceId);
+
+  chrome.test.succeed();
+}
+
+var descId0 = 'desc_id0';
+var descId1 = 'desc_id1';
+
+var changedDescs = {}
+
+chrome.bluetoothLowEnergy.onDescriptorValueChanged.addListener(function (desc) {
+  changedDescs[desc.instanceId] = desc;
+});
+
+chrome.test.sendMessage('ready', function (message) {
+  chrome.test.runTests([testDescriptorValueChanged]);
+});